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php怎么用代码给文本框输入值

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Jun 23, 2016 pm 01:20 PM

有一个文本框，一个按钮，当按了按钮后就先做个判断，如果文本框等于空则（文本框内容等于admin），如果文本框内容不等于则等于输入的内容，这段代码需要怎么写啊

if($_POST['sub']){
//获取文本框的内容
$content=$_POST['content'];
if($content==""){

如果文本框等于空则文本框内容等于"admin"

}

}

回复讨论(解决方案)

<?phpif($_POST['sub']){    //获取文本框的内容    $content=trim($_POST['content']);    if($content==""){        $content = 'admin'    }}

<?phpif($_POST['sub']){    //获取文本框的内容    $content=trim($_POST['content']);    if($content==""){        $content = 'admin'    }}

提示错误：Parse error: syntax error, unexpected '}' in D:\WWW\login.php on line 8

我的代码是：

<?phpif($_POST['sub']){    //获取文本框的内容    $content=trim($_POST['content']);    if($content==""){        $content = 'admin'    }}?>演示

你如果非要用php来判断的话：
$content = (isset( trim($_POST['content'])) && trim($_POST['content']) != '') ? trim($_POST['content']) : 'admin';
?>
或者直接在html用js来设置也是一样的

我也是醉了，php要以分号结尾的，肯定报错。

<?php/** * Created by PhpStorm. * User: Administrator * Date: 12/25/15 * Time: 9:05 AM */if ($_SERVER["REQUEST_METHOD"] == "POST") {    $aval = ($_POST['content']);    if ($aval == "")        $aval = "admin";    echo $aval;}?><html "><head>    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/></head><body><h1 id="HELLO">HELLO</h1><form name="" method="post">    <input type="text" name="content"/>    <input type="submit" value="submit" name="idbtn"/></form></body></html>

<?phpif($_POST['sub']){    //获取文本框的内容    $content=trim($_POST['content']);    if($content==""){        $content = 'admin'    }}

提示错误：Parse error: syntax error, unexpected '}' in D:\WWW\login.php on line 8

我的代码是：

<?phpif($_POST['sub']){    //获取文本框的内容    $content=trim($_POST['content']);    if($content==""){        $content = 'admin'    }}?>演示

哈哈，手误，忘了个分号。

<?php/** * Created by PhpStorm. * User: Administrator * Date: 12/25/15 * Time: 9:05 AM */if ($_SERVER["REQUEST_METHOD"] == "POST") {    $aval = ($_POST['content']);    if ($aval == "")        $aval = "admin";    echo $aval;}?><html "><head>    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/></head><body><h1 id="HELLO">HELLO</h1><form name="" method="post">    <input type="text" name="content"/>    <input type="submit" value="submit" name="idbtn"/></form></body></html>

你这个代码是将值显示到， echo $aval; 页面上，我想让他显示到这个content文本框内容，

用js实现显示到文本框

<?phpif($_POST['sub']){    //获取文本框的内容    $content=trim($_POST['content']);    if($content==""){        $content = 'admin'    }}

提示错误：Parse error: syntax error, unexpected '}' in D:\WWW\login.php on line 8

我的代码是：

<?phpif($_POST['sub']){    //获取文本框的内容    $content=trim($_POST['content']);    if($content==""){        $content = 'admin'    }}?>演示

哈哈，手误，忘了个分号。
不行了，加了;分好不提示错误了，但是按了之后没有反应，文本框也没有 admin

用js实现显示到文本框

JS我知道，我想用php来实现

昨天没有看懂你的意思，今天基本看懂你的意思了。你其实就是想用php来做js应该做的事情，这是多余的。php是服务器端脚本，不能操作dom，你如果非要这么做那得有数据库或者是要设置session，这样做是杀鸡用牛刀。php给文本赋值多在于修改数据用。因为php是通过网页请求来交互数据的，需要刷新页面(当然也可以不刷新页面，那就要用ajax后台无刷新交互了)，所以你不用js那用session？用完了还得销毁这个session？何必多此一举？

if($_POST['sub']){
    //获取文本框的内容
    $content=trim($_POST['content']);
    if($content==""){
        $content = 'admin'
    }
}

?>

演示

这样不就可以了吗？但是这样有什么意义呢？

我有数据库，用session，我就是这个意思呢，管他杀猪杀鸡的，好用就行了。需要怎么做呢

那你就提交的时候取值然后赋值给文本框，根据自己的要求在需要的时候销毁session就行了
if (isset($_POST['content']) && trim($_POST['content'])){
$content = trim($_POST['content']);
$_SESSION['content' ] = $content;
}
//这个session在你用完之后销毁，不销毁估计问题也不大，只要不重复名称就可以。
?>

演示

这样应该是可以的，你测试一下，基本思路是这样，如果测试不成功你看下有没有哪个地方少了分号什么的。

演示

这样应该是可以的，你测试一下，基本思路是这样，如果测试不成功你看下有没有哪个地方少了分号什么的。

前面php那边有错，你是要如果文本框为空设置为admin对吧？
  $content = trim($_POST['content']);
  if ($content == ''){
    $content = 'admin';
  }
  $_SESSION['content'] = $content;
?>

演示

这样应该是可以的，你测试一下，基本思路是这样，如果测试不成功你看下有没有哪个地方少了分号什么的。

<?php  $content = trim($_POST['content']);  if ($content == ''){    $content = 'admin';  }  $_SESSION['content'] = $content;?><html><head><title>演示</title></head><body><form name="form1" method="post"><input type="input" name="content" value="<?php (isset($_SESSION['content']) && $_SESSION['content']) ? $_SESSION['content']:''; ?>"/><input type="submit" name="sub"  value="提交"/></form> </body></html>

文本框为空的时候点击按钮，文本框也没有显示admin啊

演示

这样应该是可以的，你测试一下，基本思路是这样，如果测试不成功你看下有没有哪个地方少了分号什么的。

<?php  $content = trim($_POST['content']);  if ($content == ''){    $content = 'admin';  }  $_SESSION['content'] = $content;?><html><head><title>演示</title></head><body><form name="form1" method="post"><input type="input" name="content" value="<?php (isset($_SESSION['content']) && $_SESSION['content']) ? $_SESSION['content']:''; ?>"/><input type="submit" name="sub"  value="提交"/></form> </body></html>

文本框为空的时候点击按钮，文本框也没有显示admin啊

晕啊，大哥，好歹你自己也测试测试嘛，我给你个思路你要去修改一下的，你的那个表单你没发现没有href吗？那提交到哪里去处理呢对不对？下面这段代码无误，我已经测试了，记得表单的href地址改成你自己的。
  if (isset($_POST['content'])){
   $content = trim($_POST['content']);
   if ($content == ''){
      $content = 'admin';
    }
    $_SESSION['content'] = $content;
  }
?>

测试

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