PHP中用header的具体使用技巧

我们在1、location和“:”号间不能有空格，否则会出错。

2、在用header前不能有任何的输出。

3、PHP中用header后的PHP代码还会被执行。

下面是和asp中重定向response.redirect的比较：

例1:

response.redirect "../test.asp"

header("location:../test.php");

两者区别:

asp的redirect函数可以在向客户发送头文件后起作用.

如

<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span class="tag-name">head</span><span class="tag">></span><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span class="tag-name">body</span><span class="tag">></span></span></span></span></font></strong><span> </span></span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span>%response.redirect "../test.asp"%</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">body</span><span class="tag">></span><span class="tag"></span><span class="tag-name">html</span><span class="tag">></span></font></strong><span> </span>
</li>
</ol>

查是PHP中用header中下例代码会报错:

<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span class="tag-name">head</span><span class="tag">></span><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span class="tag-name">body</span><span class="tag">></span></span></span></span></font></strong><span> </span></span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span> </span>
</li>
<li class="alt">
<span></span><span class="tag-name"><strong><font color="#006699">header</font></strong></span><span>("location:../test.php");  </span>
</li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">body</span><span class="tag">></span><span class="tag"></span><span class="tag-name">html</span><span class="tag">></span></font></strong><span> </span>
</li>
</ol>

只能这样:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><strong><font color="#006699"></font></strong></span><span> </span></span></li>
<li class="">
<span></span><span class="tag-name"><strong><font color="#006699">header</font></strong></span><span>("location:../test.php");  </span>
</li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span class="tag-name">head</span><span class="tag">></span><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span class="tag-name">body</span><span class="tag">></span></span></span></span></font></strong><span>...</span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">body</span><span class="tag">></span><span class="tag"></span><span class="tag-name">html</span><span class="tag">></span></font></strong><span> </span>
</li>
</ol>

即PHP中用header函数之前不能向客户发送任何数据.

例2:

asp中

<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span class="tag-name">head</span><span class="tag">></span><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span class="tag-name">body</span><span class="tag">></span></span></span></span></font></strong><span> </span></span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span>%  </span>
</li>
<li class="alt"><span>response.redirect "../a.asp"  </span></li>
<li class=""><span>response.redirect "../b.asp"  </span></li>
<li class="alt">
<span>%</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">body</span><span class="tag">></span><span class="tag"></span><span class="tag-name">html</span><span class="tag">></span></font></strong><span> </span>
</li>
</ol>

结果是重定向a.asp文件.

php呢?

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><strong><font color="#006699"></font></strong></span><span> </span></span></li>
<li class="">
<span></span><span class="tag-name"><strong><font color="#006699">header</font></strong></span><span>("location:../a.php");  </span>
</li>
<li class="alt"><span>header("location:../b.php");  </span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span class="tag-name">head</span><span class="tag">></span><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span class="tag-name">body</span><span class="tag">></span><span class="tag"></span><span class="tag-name">body</span><span class="tag">></span><span class="tag"></span><span class="tag-name">html</span><span class="tag">></span></span></span></span></font></strong><span> </span>
</li>
</ol>

我们发现它重定向b.php.

原来在asp中执行redirect后不会再执行后面的代码.

而php在执行header后,继续执行下面的代码.

在这方面上php中的header重定向不如asp中的重定向.有时我们要重定向后,不能执行后面的代码:

一般地我们用

<ol class="dp-xml">
<li class="alt"><span><span>if(...)  </span></span></li>
<li class=""><span>header("...");  </span></li>
<li class="alt"><span>else  </span></li>
<li class=""><span>{  </span></li>
<li class="alt"><span>...  </span></li>
<li class=""><span>}  </span></li>
</ol>

但是我们可以简单的用下面的方法:

<ol class="dp-xml">
<li class="alt"><span><span>if(...)  </span></span></li>
<li class=""><span>{ header("...");exit();}  </span></li>
</ol>

PHP中用header还要注意的是，如果是用Unicode(UTF-8)编码时也会出现问题，需要调整缓存设置.

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><strong><font color="#006699"></font></strong></span><span>[</span><span class="attribute"><font color="#ff0000">email</font></span><span>=%@]%@</span><span class="attribute"><font color="#ff0000">LANGUAGE</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"VBSCRIPT[/email]"</font></span><span> </span><span class="attribute"><font color="#ff0000">CODEPAGE</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"936"</font></span><span>%</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span></span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span>%if Request.ServerVariables("SERVER_NAME")="s.jb51.net" then  </span>
</li>
<li class="alt"><span>response.redirect "news/index.htm"  </span></li>
<li class="">
<span>else%</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span>
</li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span>%end if%</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">script</span><span class="tag">></span></span></font></strong><span> </span>
</li>
<li class="alt">
<span>var </span><span class="attribute"><font color="#ff0000">url</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">location</font></span><span>.href;  </span>
</li>
<li class="">
<span>if(url.indexOf('http://www.jb51.net/')!=-1)</span><span class="attribute"><font color="#ff0000">location.href</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">'/index/index.htm'</font></span><span>;  </span>
</li>
<li class="alt">
<span>if(url.indexOf('http://www.kanshule.com/')!=-1)</span><span class="attribute"><font color="#ff0000">location.href</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">'/index1/index.htm'</font></span><span>;  </span>
</li>
<li class="">
<span>if(url.indexOf('http://www.shouji17.com/')!=-1)</span><span class="attribute"><font color="#ff0000">location.href</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">'/cn/index.asp'</font></span><span>;  </span>
</li>
<li class="alt">
<span>if(url.indexOf('http://www.baidu.com/')!=-1)</span><span class="attribute"><font color="#ff0000">location.href</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">'/cn/index.asp'</font></span><span>;  </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">script</span><span class="tag">></span></font></strong><span> </span>
</li>
</ol>