对于下面一段js代码
<?php
var excuteScript = function (id, scriptSource, charset) {
var head = document.getElementsByTagName(‘head’)[0];
var oldScript = document.getElementById(id);
if (oldScript) {
head.removeChild(oldScript);
}
var newScript = document.createElement(‘script’);
if (charset) {
newScript.charset = charset;
} else {
newScript.charset = ‘gb2312’;
}
newScript.id = id;
newScript.type = ‘text/javascript’;
scriptSource += (/?/.test(scriptSource)?"&":"?") + "_=" + (new Date()).getTime();
newScript.src = scriptSource;
head.appendChild(newScript);
};
?>
对于IE和firefox是有所不同的：
IE： 请求发起在给script标签的src属性赋值的时候，至少ie8是这样
Firefox： 请求发起于appendChild的时候，如果创建的标签没有append操作，将不会发起请求； 至少firefox 3.0.11 是这样
我们可以通过下面的脚本测试一下：
<html>
<head><title>test script </title></head>
<body>
<script>
scriptSource = "http://phpor.net/404.js";
var head = document.getElementsByTagName(‘head’)[0];
var oldScript = document.getElementById(id);
if (oldScript) {
head.removeChild(oldScript);
}
var newScript = document.createElement(‘script’);
newScript.charset = ‘gb2312’;
newScript.id = "testid";
newScript.type = ‘text/javascript’;
newScript.src = scriptSource;
newScript.src = scriptSource +"?2";
//head.appendChild(newScript);
</script>
</body>
</html>