简单的javascript翻转器

window.onload=rolloverInit;    
function rolloverInit(){
    for(var i=0;i<document.images.length;i++){
        if(document.images[i].parentNode.tagName == "A"){
            setupRollover(document.images[i]);
        }
    }
}

function setupRollover(thisImage){
    thisImage.outImage = new Image();
    thisImage.outImage.src = thisImage.src;
    thisImage.onmouseout = function(){
        this.src = this.outImage.src;
    }

    thisImage.overImage = new Image();
    thisImage.overImage.src = "images/"+thisImage.id+"_2.jpg";
    thisImage.onmouseover = function(){
        this.src=this.overImage.src;
    }
}