判断页面及其中的iframe是否加载完毕
<script>
//判断页面加载情况
function addLoadEvent(func) {
var oldonload = window.onload;
if (typeof window.onload != 'function') {
window.onload = func;
} else {
window.onload = function() {
if (oldonload) {
oldonload();
}
func();
}
}
}
function overWeb() {
alert('页面加载完毕！');
}
addLoadEvent(overWeb);
</script>
2.判断页面dom的部分元素是否加载完毕
<script>
//DOM-ready watcher
function domFunction(f, a)
{
//initialise the counter
var n = 0;
//start the timer
var t = setInterval(function()
{
//continue flag indicates whether to continue to the next iteration
//assume that we are going unless specified otherwise
var c = true;
//increase the counter
n++;
//if DOM methods are supported, and the body element exists
//(using a double-check including document.body, for the benefit of older moz builds [eg ns7.1]
//in which getElementsByTagName('body')[0] is undefined, unless this script is in the body section)
if(typeof document.getElementsByTagName != 'undefined' && (document.getElementsByTagName('body')[0] != null || document.body != null))
{
//set the continue flag to false
//because other things being equal, we're not going to continue
c = false;
//but ... if the arguments object is there
if(typeof a == 'object')
{
//iterate through the object
for(var i in a)
{
//if its value is "id" and the element with the given ID doesn't exist
//or its value is "tag" and the specified collection has no members
if
(
(a[i] == 'id' && document.getElementById(i) == null)
||
(a[i] == 'tag' && document.getElementsByTagName(i).length < 1)
)
{
//set the continue flag back to true
//because a specific element or collection doesn't exist
c = true;
//no need to finish this loop
break;
}
}
}
//if we're not continuing
//we can call the argument function and clear the timer
if(!c) { f(); clearInterval(t); }
}
//if the timer has reached 60 (so timeout after 15 seconds)
//in practise, I've never seen this take longer than 7 iterations [in kde 3
//in second place was IE6, which takes 2 or 3 iterations roughly 5% of the time]
if(n >= 60)
{
//clear the timer
clearInterval(t);
}
}, 250);
};
function myFunction()
{
alert("The DOM is ready");
};
var foobar = new domFunction(myFunction, {'iframe' : 'tag'});
</script>
<body>
<h1>domFunction</h1>
<iframe src="about:blank"></iframe><iframe src="about:blank"></iframe><iframe src="about:blank"></iframe>
<p id="poster"><img src="http://www.brothercake.com/scripts/iotbs/iotbs.bmp" alt="Invasion of the Body Snatchers poster (1956)" /></p>
</body>
3.用异步方法判断,其中的iframe是否加载完毕
<iframe src="http://www.baidu.com/" onreadystatechange="if(this.readyState=='complete')alert('IFRAME加载完成了!!');"></iframe>
但是：
iframe onreadystatechange的事件只用于ie5.5以上版本
frame不支持onreadystatechange的事件
判断代码可以加在装载的页面内作判别
document.onreadystatechange = function(){
alert("load OK");
}
