判断脚本，图片，CSS，iframe等是否加载完成

1.图片

<img id="MyImg" src="src"/>
jquery实现：
$("#MyImg").load(function(){
})
说明：在jquery中load方法是在对象加载完毕后触发

javascript实现：

JS判断img图片是否加载完成：使用onload或者onreadystatechange

function   isImgLoad(){
    if(!!window.ActiveXObject){  // IE
        if(img.readyState == 'complete'){
            alert('finished');
        }
        else{
            alert('loading');
        }
    }
    else{
        // 非IE
        if(img.complete == true){
            alert('finished');
        }
        else{
            alert('loading');
        }
    }
}

2.动态加载js,css文件

function loadjscssfile(filename,filetype){

if(filetype == "js"){

var fileref = document.createElement('script');

fileref.setAttribute("type","text/javascript");

fileref.setAttribute("src",filename);

}else if(filetype == "css"){

var fileref = document.createElement('link');

fileref.setAttribute("rel","stylesheet");

fileref.setAttribute("type","text/css");

fileref.setAttribute("href",filename);

}

if(typeof fileref != "undefined"){

document.getElementsByTagName("head")[0].appendChild(fileref);

}

}

loadjscssfile("do.js","js");

loadjscssfile("test.css","css");

3.判断iframe是否加载完成

var iframe = document.createElement("iframe");

iframe.src = "http://www.jb51.net";

if (!/*@cc_on!@*/0) { //if not IE

iframe.onload = function(){

alert("Local iframe is now loaded.");

};

} else {

iframe.onreadystatechange = function(){

if (iframe.readyState == "complete"){

alert("Local iframe is now loaded.");

}

};

}

document.body.appendChild(iframe);

或者：

var iframe = document.createElement("iframe");

iframe.src = "http://www.jb51.net";

if (iframe.attachEvent){

iframe.attachEvent("onload", function(){

alert("Local iframe is now loaded.");

});

} else {

iframe.onload = function(){

alert("Local iframe is now loaded.");

};

}

document.body.appendChild(iframe);