How to implement verification code in php
Verification codes are implemented more and more in forms, but verification codes written in js always feel inconvenient, so I learned verification codes implemented in php.
Verification codes are implemented more and more in forms, but verification codes written in js always feel inconvenient, so I learned about verification codes implemented in php. Well, I actually had nothing to do, but I didn’t want to waste time, so I learned how to implement verification codes in PHP. As the saying goes, having too many skills does not weigh you down. Moreover, it can also be encapsulated into a function, which is very convenient for future use. Of course, it is not encapsulated now.
Now let’s talk about the simple purely numerical verification code.
If you are a beginner, it is recommended to follow the comments of my code //Numbers step by step. The easiest way is to copy the entire code.
Create a new captcha.php:
<ol class="dp-c"><li class="alt"><span><span>php </span></span></li><li><span> <span class="comment">//10>设置session,必须处于脚本最顶部</span><span> </span></span></li><li class="alt"><span> session_start(); </span></li><li><span> </span></li><li class="alt"><span> <span class="vars">$image</span><span> = imagecreatetruecolor(100, 30); </span><span class="comment">//1>设置验证码图片大小的函数</span><span> </span></span></li><li><span> <span class="comment">//5>设置验证码颜色 imagecolorallocate(int im, int red, int green, int blue);</span><span> </span></span></li><li class="alt"><span> <span class="vars">$bgcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,255,255,255); </span><span class="comment">//#ffffff</span><span> </span></span></li><li><span> <span class="comment">//6>区域填充 int imagefill(int im, int x, int y, int col) (x,y) 所在的区域着色,col 表示欲涂上的颜色</span><span> </span></span></li><li class="alt"><span> imagefill(<span class="vars">$image</span><span>, 0, 0, </span><span class="vars">$bgcolor</span><span>); </span></span></li><li><span> <span class="comment">//10>设置变量</span><span> </span></span></li><li class="alt"><span> <span class="vars">$captcha_code</span><span> = </span><span class="string">""</span><span>; </span></span></li><li><span> <span class="comment">//7>生成随机数字</span><span> </span></span></li><li class="alt"><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><4;</span><span class="vars">$i</span><span>++){ </span></span></li><li><span> <span class="comment">//设置字体大小</span><span> </span></span></li><li class="alt"><span> <span class="vars">$fontsize</span><span> = 6; </span></span></li><li><span> <span class="comment">//设置字体颜色,随机颜色</span><span> </span></span></li><li class="alt"><span> <span class="vars">$fontcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>, rand(0,120),rand(0,120), rand(0,120)); </span><span class="comment">//0-120深颜色</span><span> </span></span></li><li><span> <span class="comment">//设置数字</span><span> </span></span></li><li class="alt"><span> <span class="vars">$fontcontent</span><span> = rand(0,9); </span></span></li><li><span> <span class="comment">//10>.=连续定义变量</span><span> </span></span></li><li class="alt"><span> <span class="vars">$captcha_code</span><span> .= </span><span class="vars">$fontcontent</span><span>; </span></span></li><li><span> <span class="comment">//设置坐标</span><span> </span></span></li><li class="alt"><span> <span class="vars">$x</span><span> = (</span><span class="vars">$i</span><span>*100/4)+rand(5,10); </span></span></li><li><span> <span class="vars">$y</span><span> = rand(5,10); </span></span></li><li class="alt"><span> </span></li><li><span> imagestring(<span class="vars">$image</span><span>,</span><span class="vars">$fontsize</span><span>,</span><span class="vars">$x</span><span>,</span><span class="vars">$y</span><span>,</span><span class="vars">$fontcontent</span><span>,</span><span class="vars">$fontcolor</span><span>); </span></span></li><li class="alt"><span> } </span></li><li><span> <span class="comment">//10>存到session</span><span> </span></span></li><li class="alt"><span> <span class="vars">$_SESSION</span><span>[</span><span class="string">'authcode'</span><span>] = </span><span class="vars">$captcha_code</span><span>; </span></span></li><li><span> <span class="comment">//8>增加干扰元素,设置雪花点</span><span> </span></span></li><li class="alt"><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><200;</span><span class="vars">$i</span><span>++){ </span></span></li><li><span> <span class="comment">//设置点的颜色,50-200颜色比数字浅,不干扰阅读</span><span> </span></span></li><li class="alt"><span> <span class="vars">$pointcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,rand(50,200), rand(50,200), rand(50,200)); </span></span></li><li><span> <span class="comment">//imagesetpixel — 画一个单一像素</span><span> </span></span></li><li class="alt"><span> imagesetpixel(<span class="vars">$image</span><span>, rand(1,99), rand(1,29), </span><span class="vars">$pointcolor</span><span>); </span></span></li><li><span> } </span></li><li class="alt"><span> <span class="comment">//9>增加干扰元素,设置横线</span><span> </span></span></li><li><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><4;</span><span class="vars">$i</span><span>++){ </span></span></li><li class="alt"><span> <span class="comment">//设置线的颜色</span><span> </span></span></li><li><span> <span class="vars">$linecolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,rand(80,220), rand(80,220),rand(80,220)); </span></span></li><li class="alt"><span> <span class="comment">//设置线,两点一线</span><span> </span></span></li><li><span> imageline(<span class="vars">$image</span><span>,rand(1,99), rand(1,29),rand(1,99), rand(1,29),</span><span class="vars">$linecolor</span><span>); </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">//2>设置头部,image/png</span><span> </span></span></li><li><span> header(<span class="string">'Content-Type: image/png'</span><span>); </span></span></li><li class="alt"><span> <span class="comment">//3>imagepng() 建立png图形函数</span><span> </span></span></li><li><span> imagepng(<span class="vars">$image</span><span>); </span></span></li><li class="alt"><span> <span class="comment">//4>imagedestroy() 结束图形函数 销毁$image</span><span> </span></span></li><li><span> imagedestroy(<span class="vars">$image</span><span>); </span></span></li></ol>
Then comes the code for the static page: index.html
<ol class="dp-c"><li class="alt"><span><span>doctype html> </span></span></li><li><span><html> </span></li><li class="alt"><span> <head> </span></li><li><span> <meta http-equiv=<span class="string">"Content-Type"</span><span> content=</span><span class="string">"text/html; charset=UTF-8"</span><span>> </span></span></li><li class="alt"><span> <title>确认验证码title> </span></li><li><span> head> </span></li><li class="alt"><span> <body> </span></li><li><span> <form method=<span class="string">"post"</span><span> action=</span><span class="string">"./form.php"</span><span>> </span></span></li><li class="alt"><span> <p>验证码: <img id=<span class="string" alt="How to implement verification code in php_PHP tutorial" >"captcha_img"</span><span> border=</span><span class="string">'1'</span><span> src=</span><span class="string">'./captcha.php?r=echo rand(); ?>'</span><span> style=</span><span class="string">"width:100px; height:30px"</span><span> /> </span></span></li><li><span> <a href=<span class="string">"javascript:void(0)"</span><span> onclick=</span><span class="string">"document.getElementById('captcha_img').src='./captcha.php?r='+Math.random()"</span><span>>换一个?a> </span></span></li><li class="alt"><span> p> </span></li><li><span> <P>请输入验证码:<input type=<span class="string">"text"</span><span> name=</span><span class="string">'authcode'</span><span> value=</span><span class="string">''</span><span>/>p> </span></span></li><li class="alt"><span> <p><input type=<span class="string">'submit'</span><span> value=</span><span class="string">'提交'</span><span> style=</span><span class="string">'padding:6px 5px;'</span><span>/>p> </span></span></li><li><span> body> </span></li><li class="alt"><span>html> <br /></span></li></ol>
As you can see from index.html, the submitted form goes to form.php, so there is also a form.php code for judgment:
<ol class="dp-c"><li class="alt"><span><span>php </span></span></li><li><span> header(<span class="string">"Content-Type:text/html;charset=utf-8"</span><span>); </span><span class="comment">//设置头部信息</span><span> </span></span></li><li class="alt"><span> <span class="comment">//isset()检测变量是否设置</span><span> </span></span></li><li><span> <span class="keyword">if</span><span>(isset(</span><span class="vars">$_REQUEST</span><span>[</span><span class="string">'authcode'</span><span>])){ </span></span></li><li class="alt"><span> session_start(); </span></li><li><span> <span class="comment">//strtolower()小写函数</span><span> </span></span></li><li class="alt"><span> <span class="keyword">if</span><span>(</span><span class="func">strtolower</span><span>(</span><span class="vars">$_REQUEST</span><span>[</span><span class="string">'authcode'</span><span>])== </span><span class="vars">$_SESSION</span><span>[</span><span class="string">'authcode'</span><span>]){ </span></span></li><li><span> <span class="comment">//跳转页面</span><span> </span></span></li><li class="alt"><span> <span class="func">echo</span><span> </span><span class="string">"<script language=\"javascript\">"</span><span>; </span></span></li><li><span> <span class="func">echo</span><span> </span><span class="string">"document.location=\"./form.php\""</span><span>; </span></span></li><li class="alt"><span> <span class="func">echo</span><span> </span><span class="string">"</script>"</span><span>; </span></span></li><li><span> }<span class="keyword">else</span><span>{ </span></span></li><li class="alt"><span> <span class="comment">//提示以及跳转页面</span><span> </span></span></li><li><span> <span class="func">echo</span><span> </span><span class="string">"<script language=\"javascript\">"</span><span>; </span></span></li><li class="alt"><span> <span class="func">echo</span><span> </span><span class="string">"alert('输入错误!');"</span><span>; </span></span></li><li><span> <span class="func">echo</span><span> </span><span class="string">"document.location=\"./form.php\""</span><span>; </span></span></li><li class="alt"><span> <span class="func">echo</span><span> </span><span class="string">"</script>"</span><span>; </span></span></li><li><span> } </span></li><li class="alt"><span> <span class="func">exit</span><span>(); </span></span></li><li><span> } <br /></span></li></ol>
The page displayed is as follows:
Then, if pure numbers are implemented, it should not be difficult to add numbers and English. The code to be modified is just to change captcha.php to //7>Generate random numbers to //7> Generate random letters and numbers , if you are really cute and think it can be achieved by modifying these words, then congratulations, you will always be happy. Brain-disabled children have a lot of fun.
No more nonsense, let’s pull the code.
<ol class="dp-c"><li class="alt"><span><span>php </span></span></li><li><span> <span class="comment">//10>设置session,必须处于脚本最顶部</span><span> </span></span></li><li class="alt"><span> session_start(); </span></li><li><span> </span></li><li class="alt"><span> <span class="vars">$image</span><span> = imagecreatetruecolor(100, 30); </span><span class="comment">//1>设置验证码图片大小的函数</span><span> </span></span></li><li><span> <span class="comment">//5>设置验证码颜色 imagecolorallocate(int im, int red, int green, int blue);</span><span> </span></span></li><li class="alt"><span> <span class="vars">$bgcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,255,255,255); </span><span class="comment">//#ffffff</span><span> </span></span></li><li><span> <span class="comment">//6>区域填充 int imagefill(int im, int x, int y, int col) (x,y) 所在的区域着色,col 表示欲涂上的颜色</span><span> </span></span></li><li class="alt"><span> imagefill(<span class="vars">$image</span><span>, 0, 0, </span><span class="vars">$bgcolor</span><span>); </span></span></li><li><span> <span class="comment">//10>设置变量</span><span> </span></span></li><li class="alt"><span> <span class="vars">$captcha_code</span><span> = </span><span class="string">""</span><span>; </span></span></li><li><span> <span class="comment">//7>生成随机的字母和数字</span><span> </span></span></li><li class="alt"><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><4;</span><span class="vars">$i</span><span>++){ </span></span></li><li><span> <span class="comment">//设置字体大小</span><span> </span></span></li><li class="alt"><span> <span class="vars">$fontsize</span><span> = 8; </span></span></li><li><span> <span class="comment">//设置字体颜色,随机颜色</span><span> </span></span></li><li class="alt"><span> <span class="vars">$fontcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>, rand(0,120),rand(0,120), rand(0,120)); </span><span class="comment">//0-120深颜色</span><span> </span></span></li><li><span> <span class="comment">//设置需要随机取的值,去掉容易出错的值如0和o</span><span> </span></span></li><li class="alt"><span> <span class="vars">$data</span><span> =</span><span class="string">'abcdefghigkmnpqrstuvwxy3456789'</span><span>; </span></span></li><li><span> <span class="comment">//取出值,字符串截取方法 strlen获取字符串长度</span><span> </span></span></li><li class="alt"><span> <span class="vars">$fontcontent</span><span> = </span><span class="func">substr</span><span>(</span><span class="vars">$data</span><span>, rand(0,</span><span class="func">strlen</span><span>(</span><span class="vars">$data</span><span>)),1); </span></span></li><li><span> <span class="comment">//10>.=连续定义变量</span><span> </span></span></li><li class="alt"><span> <span class="vars">$captcha_code</span><span> .= </span><span class="vars">$fontcontent</span><span>; </span></span></li><li><span> <span class="comment">//设置坐标</span><span> </span></span></li><li class="alt"><span> <span class="vars">$x</span><span> = (</span><span class="vars">$i</span><span>*100/4)+rand(5,10); </span></span></li><li><span> <span class="vars">$y</span><span> = rand(5,10); </span></span></li><li class="alt"><span> </span></li><li><span> imagestring(<span class="vars">$image</span><span>,</span><span class="vars">$fontsize</span><span>,</span><span class="vars">$x</span><span>,</span><span class="vars">$y</span><span>,</span><span class="vars">$fontcontent</span><span>,</span><span class="vars">$fontcolor</span><span>); </span></span></li><li class="alt"><span> } </span></li><li><span> <span class="comment">//10>存到session</span><span> </span></span></li><li class="alt"><span> <span class="vars">$_SESSION</span><span>[</span><span class="string">'authcode'</span><span>] = </span><span class="vars">$captcha_code</span><span>; </span></span></li><li><span> <span class="comment">//8>增加干扰元素,设置雪花点</span><span> </span></span></li><li class="alt"><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><200;</span><span class="vars">$i</span><span>++){ </span></span></li><li><span> <span class="comment">//设置点的颜色,50-200颜色比数字浅,不干扰阅读</span><span> </span></span></li><li class="alt"><span> <span class="vars">$pointcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,rand(50,200), rand(50,200), rand(50,200)); </span></span></li><li><span> <span class="comment">//imagesetpixel — 画一个单一像素</span><span> </span></span></li><li class="alt"><span> imagesetpixel(<span class="vars">$image</span><span>, rand(1,99), rand(1,29), </span><span class="vars">$pointcolor</span><span>); </span></span></li><li><span> } </span></li><li class="alt"><span> <span class="comment">//9>增加干扰元素,设置横线</span><span> </span></span></li><li><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><4;</span><span class="vars">$i</span><span>++){ </span></span></li><li class="alt"><span> <span class="comment">//设置线的颜色</span><span> </span></span></li><li><span> <span class="vars">$linecolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,rand(80,220), rand(80,220),rand(80,220)); </span></span></li><li class="alt"><span> <span class="comment">//设置线,两点一线</span><span> </span></span></li><li><span> imageline(<span class="vars">$image</span><span>,rand(1,99), rand(1,29),rand(1,99), rand(1,29),</span><span class="vars">$linecolor</span><span>); </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">//2>设置头部,image/png</span><span> </span></span></li><li><span> header(<span class="string">'Content-Type: image/png'</span><span>); </span></span></li><li class="alt"><span> <span class="comment">//3>imagepng() 建立png图形函数</span><span> </span></span></li><li><span> imagepng(<span class="vars">$image</span><span>); </span></span></li><li class="alt"><span> <span class="comment">//4>imagedestroy() 结束图形函数 销毁$image</span><span> </span></span></li><li><span> imagedestroy(<span class="vars">$image</span><span>); </span></span></li></ol>
The other two pages are not allowed to be modified.
Generally speaking, this is enough for now. But just like anime, there will always be extras.
So, let’s do a side story about Chinese characters. In fact, I am also planning to put the Chinese character verification code into my graduation project. Although sliding verification codes are very popular now, I am not specialized in learning js after all.
Moreover, you can also tell the defending teacher that our verification code does not require materials, even the pictures are generated, and there is nothing to pretend to be 13 with your own knowledge.
<ol class="dp-c"><li class="alt"><span><span>php </span></span></li><li><span> <span class="comment">//11>设置session,必须处于脚本最顶部</span><span> </span></span></li><li class="alt"><span> session_start(); </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">//1>设置验证码图片大小的函数</span><span> </span></span></li><li><span> <span class="vars">$image</span><span> = imagecreatetruecolor(200, 60); </span></span></li><li class="alt"><span> <span class="comment">//5>设置验证码颜色 imagecolorallocate(int im, int red, int green, int blue);</span><span> </span></span></li><li><span> <span class="vars">$bgcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,255,255,255); </span><span class="comment">//#ffffff</span><span> </span></span></li><li class="alt"><span> <span class="comment">//6>区域填充 int imagefill(int im, int x, int y, int col) (x,y) 所在的区域着色,col 表示欲涂上的颜色</span><span> </span></span></li><li><span> imagefill(<span class="vars">$image</span><span>, 0, 0, </span><span class="vars">$bgcolor</span><span>); </span></span></li><li class="alt"><span> <span class="comment">//7>设置ttf字体</span><span> </span></span></li><li><span> <span class="vars">$fontface</span><span> = </span><span class="string">'FZYTK.TTF'</span><span>; </span></span></li><li class="alt"><span> <span class="comment">//7>设置字库,实现简单的数字储备</span><span> </span></span></li><li><span> <span class="vars">$str</span><span>=</span><span class="string">'天地不仁以万物为刍狗圣人不仁以百姓为刍狗这句经常出现在控诉暴君暴政上地残暴不仁把万物都当成低贱的猪狗来看待而那些高高在上的所谓圣人们也没两样还不是把我们老百姓也当成猪狗不如的东西但实在正取的解读是地不情感用事对万物一视同仁圣人不情感用事对百姓一视同仁执子之手与子偕老当男女主人公含情脉脉看着对方说了句执子之手与子偕老女方泪眼朦胧含羞地回一句讨厌啦这样的情节我们是不是见过很多但是我们来看看这句的原句死生契阔与子成说执子之手与子偕老于嗟阔兮不我活兮于嗟洵兮不我信兮意思是说战士之间的约定说要一起死现在和我约定的人都走了我怎么活啊赤裸裸的兄弟江湖战友友谊啊形容好基友的基情比男女之间的爱情要合适很多吧'</span><span>; </span></span></li><li class="alt"><span> <span class="comment">//str_split()切割字符串为一个数组,一个中文在utf_8为3个字符</span><span> </span></span></li><li><span> <span class="vars">$strdb</span><span> = </span><span class="func">str_split</span><span>(</span><span class="vars">$str</span><span>,3); </span></span></li><li class="alt"><span> <span class="comment">//>11</span><span> </span></span></li><li><span> <span class="vars">$captcha_code</span><span> = </span><span class="string">''</span><span>; </span></span></li><li class="alt"><span> <span class="comment">//8>生成随机的汉子</span><span> </span></span></li><li><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><4;</span><span class="vars">$i</span><span>++){ </span></span></li><li class="alt"><span> <span class="comment">//设置字体颜色,随机颜色</span><span> </span></span></li><li><span> <span class="vars">$fontcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>, rand(0,120),rand(0,120), rand(0,120)); </span><span class="comment">//0-120深颜色</span><span> </span></span></li><li class="alt"><span> <span class="comment">//随机选取中文</span><span> </span></span></li><li><span> <span class="vars">$in</span><span> = rand(0,</span><span class="func">count</span><span>(</span><span class="vars">$strdb</span><span>)); </span></span></li><li class="alt"><span> <span class="vars">$cn</span><span> = </span><span class="vars">$strdb</span><span>[</span><span class="vars">$in</span><span>]; </span></span></li><li><span> <span class="comment">//将中文记录到将保存到session的字符串中</span><span> </span></span></li><li class="alt"><span> <span class="vars">$captcha_code</span><span> .= </span><span class="vars">$cn</span><span>; </span></span></li><li><span> <span class="comment">/*imagettftext (resource $image ,float $size ,float $angle ,int $x ,int $y,int $color,</span> </span></li><li class="alt"><span><span class="comment"> string $fontfile ,string $text ) 幕布 ,尺寸,角度,坐标,颜色,字体路径,文本字符串</span> </span></li><li><span><span class="comment"> mt_rand()生成更好的随机数,比rand()快四倍*/</span><span> </span></span></li><li class="alt"><span> imagettftext(<span class="vars">$image</span><span>, mt_rand(20,24),mt_rand(-60,60),(40*</span><span class="vars">$i</span><span>+20),mt_rand(30,35),</span><span class="vars">$fontcolor</span><span>,</span><span class="vars">$fontface</span><span>,</span><span class="vars">$cn</span><span>); </span></span></li><li><span> } </span></li><li class="alt"><span> <span class="comment">//11>存到session</span><span> </span></span></li><li><span> <span class="vars">$_SESSION</span><span>[</span><span class="string">'authcode'</span><span>] = </span><span class="vars">$captcha_code</span><span>; </span></span></li><li class="alt"><span> <span class="comment">//9>增加干扰元素,设置点</span><span> </span></span></li><li><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><200;</span><span class="vars">$i</span><span>++){ </span></span></li><li class="alt"><span> <span class="comment">//设置点的颜色,50-200颜色比数字浅,不干扰阅读</span><span> </span></span></li><li><span> <span class="vars">$pointcolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,rand(50,200), rand(50,200), rand(50,200)); </span></span></li><li class="alt"><span> <span class="comment">//imagesetpixel — 画一个单一像素</span><span> </span></span></li><li><span> imagesetpixel(<span class="vars">$image</span><span>, rand(1,199), rand(1,59), </span><span class="vars">$pointcolor</span><span>); </span></span></li><li class="alt"><span> } </span></li><li><span> <span class="comment">//10>增加干扰元素,设置线</span><span> </span></span></li><li class="alt"><span> <span class="keyword">for</span><span>(</span><span class="vars">$i</span><span>=0;</span><span class="vars">$i</span><span><4;</span><span class="vars">$i</span><span>++){ </span></span></li><li><span> <span class="comment">//设置线的颜色</span><span> </span></span></li><li class="alt"><span> <span class="vars">$linecolor</span><span> = imagecolorallocate(</span><span class="vars">$image</span><span>,rand(80,220), rand(80,220),rand(80,220)); </span></span></li><li><span> <span class="comment">//设置线,两点一线</span><span> </span></span></li><li class="alt"><span> imageline(<span class="vars">$image</span><span>,rand(1,199), rand(1,59),rand(1,199), rand(1,59),</span><span class="vars">$linecolor</span><span>); </span></span></li><li><span> } </span></li><li class="alt"><span> </span></li><li><span> <span class="comment">//2>设置头部,image/png</span><span> </span></span></li><li class="alt"><span> header(<span class="string">'Content-Type: image/png'</span><span>); </span></span></li><li><span> <span class="comment">//3>imagepng() 建立png图形函数</span><span> </span></span></li><li class="alt"><span> imagepng(<span class="vars">$image</span><span>); </span></span></li><li><span> <span class="comment">//4>imagedestroy() 结束图形函数 销毁$image</span><span> </span></span></li><li class="alt"><span> imagedestroy(<span class="vars">$image</span><span>); </span></span></li></ol>
Other pages do not need to be modified.
The rendering is as follows:


php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

在PHP中,可以利用implode()函数的第一个参数来设置没有分隔符,该函数的第一个参数用于规定数组元素之间放置的内容,默认是空字符串,也可将第一个参数设置为空,语法为“implode(数组)”或者“implode("",数组)”。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。


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