Uncaught TypeError: window.showModalDialog is not a function 谷歌

//新版本谷歌没有window.showModalDialog，创建一个window.open
if(window.showModalDialog == undefined){  
window.showModalDialog = function(url,mixedVar,features){  
        window.hasOpenWindow = true;  
                if(mixedVar) var mixedVar = mixedVar;  
              if(features) var features = features.replace(/(dialog)|(px)/ig,"").replace(/;/g,',').replace(/\:/g,"=");  
                window.myNewWindow = window.open(url,"_blank",features);  
        }  

}

在使用回调的时候

var parent;
//谷歌的情况下
 if (window.opener != undefined) {
   parent=window.opener;
 }    
 else {   

          parent=window.dialogArguments;
}  

只要当谷歌浏览器使用window.showModalDialog未定义的时候