兼容IE/Firefox/Opera/Safari的检测页面装载完毕的脚本Ext.onReady的实现

<script type="text/javascript"><!-- 
function GOOGLEResize(){ 
alert(1); 
} 
var ua=navigator.userAgent.toLowerCase(); 
var isStrict=document.compatMode=="CSS1Compat", 
isOpera=ua.indexOf("opera")>-1, 
isSafari=(/webkit|khtml/).test(ua), 
isIE=ua.indexOf("msie")>-1, 
isIE7=ua.indexOf("msie 7")>-1, 
isGecko=!isSafari&&ua.indexOf("gecko")>-1, 
isBorderBox=isIE&&!isStrict, 
isWindows=(ua.indexOf("windows")!=-1||ua.indexOf("win32")!=-1), 
isMac=(ua.indexOf("macintosh")!=-1||ua.indexOf("mac os x")!=-1), 
isLinux=(ua.indexOf("linux")!=-1), 
isSecure=window.location.href.toLowerCase().indexOf("https")===0; 
if(isGecko || isOpera) { 
    document.addEventListener("DOMContentLoaded", GOOGLEResize, false); 
}else if(isIE){ 
    document.write("<s"+'cript id="ie-deferred-loader" defer="defer" src="/'+'/:"></s'+"cript>"); 
    var defer = document.getElementById("ie-deferred-loader"); 
    defer.onreadystatechange = function(){ 
        if(this.readyState == "complete"){ 
            GOOGLEResize(); 
        } 
    }; 
}else if(Ext.isSafari){ 
    docReadyProcId = setInterval(function(){ 
        var rs = document.readyState; 
        if(rs == "complete") { 
            GOOGLEResize(); 
         } 
    }, 10); 
}else{ 
window.onload=GOOGLEResize; 
} 
// --></script>

其中对于IE的检测很有意思。
以上代码，整理自Extjs的脚本，完全可以代替 Ext.onReady使用。