使用PHP header进行页面跳转出现的问题解疑

我们在进行页面跳转的时候，通常会用到

在PHP中用header("location:test.php")进行跳转要注意以下几点,有助于解决一些新手经常遇到的问题

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、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><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 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></span></span></span></span></li>
<li><span class="tag"><span>%response.redirect "../test.asp"%</span><span class="tag">></span><span> </span></span></li>
<li class="alt"><span class="tag"><span class="tag-name">body</span><span class="tag">></span><span class="tag"><span class="tag-name">html</span><span class="tag">></span><span> </span></span></span></li>
</ol>

查是php中下例代码会报错:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><span> </span><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span> /head</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">body</span><span class="tag">></span><span> </span></span></span></span></span></span></li>
<li>
<span class="tag"></span><span> </span>
</li>
<li class="alt">
<span class="tag-name">header</span><span>("location:../test.php");  </span>
</li>
<li>
<span class="tag">?></span><span> </span>
</li>
<li class="alt"><span class="tag"><span> /body</span><span class="tag">></span><span class="tag"><span> /html</span><span class="tag">></span><span> </span></span></span></li>
<li><span>只能这样:  </span></li>
<li class="alt"><span class="tag"><span> ?   </span></span></li>
<li><span>header("location:../test.php");  </span></li>
<li class="alt">
<span class="tag">?></span><span> </span>
</li>
<li><span class="tag"><span> </span><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span> /head</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">body</span><span class="tag">></span><span>...</span><span class="tag"><span> /body</span><span class="tag">></span><span class="tag"><span> /html</span><span class="tag">></span><span> </span></span></span></span></span></span></span></li>
</ol>

即PHP header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><span class="tag"><span> </span><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span> /head</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">body</span><span class="tag">></span><span> </span></span></span></span></span></span></li>
<li><span class="tag"><span>%  </span></span></li>
<li class="alt"><span>response.redirect "../a.asp"  </span></li>
<li><span>response.redirect "../b.asp"  </span></li>
<li class="alt">
<span>%</span><span class="tag">></span><span> </span>
</li>
<li><span class="tag"><span> /body</span><span class="tag">></span><span class="tag"><span> /html</span><span class="tag">></span><span> </span></span></span></li>
<li class="alt"><span>结果是重定向a.asp文件.  </span></li>
<li><span>php呢?  </span></li>
<li class="alt"><span class="tag"><span> ?  </span></span></li>
<li><span>header("location:../a.php");  </span></li>
<li class="alt"><span>header("location:../b.php");  </span></li>
<li>
<span class="tag">?></span><span> </span>
</li>
<li class="alt"><span class="tag"><span> </span><span class="tag-name">html</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">head</span><span class="tag">></span><span class="tag"><span> /head</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">body</span><span class="tag">></span><span class="tag"><span> /body</span><span class="tag">></span><span class="tag"><span> /html</span><span class="tag">></span><span> </span></span></span></span></span></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><span>header("...");  </span></li>
<li class="alt"><span>else  </span></li>
<li><span>{  </span></li>
<li class="alt"><span>...  </span></li>
<li><span>}  </span></li>
</ol>

但是我们可以简单的用下面的PHP header方法:

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

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PHP header的缓存设置.

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

以上就是在使用PHP header时应当注意的几点问题。