如何预加载图像，然后在完成图像加载后更改div内容

    var mydir =\'slideshow_pics/\';
var myArray = new Array();
myArray[0] = mydir+\'0.jpg\';
myArray[1] = mydir+\'1.jpg\';
myArray[2] = mydir+\'2.jpg\';
myArray[3] = mydir+\'3.jpg\';
myArray[4] = mydir+\'4.jpg\';
myArray[5] = mydir+\'5.jpg\';
myArray[6] = mydir+\'6.jpg\';
myArray[7] = mydir+\'7.jpg\';

var myWidth = new Array();
myWidth[0] = \'470\';
myWidth[1] = \'450\';
myWidth[2] = \'450\';
myWidth[3] = \'500\';
myWidth[4] = \'550\';
myWidth[5] = \'450\';
myWidth[6] = \'800\';
myWidth[7] = \'300\';

var myCheck = new Array();

function preloader(images){
         var i = 0;

         // start preloading
         for(i=0; i<=images.length; i++){
            imageObj = new Image();
            imageObj.src=images[i];
            imageObj.onLoad = check(i, images.length);
         };

    }


function checkimg(data, w) {
        p=0;
        z=0;
        o = \'no\';
        var myImg = new Image();
        myImg.src = data;

        while (p == 0) {

            if (myImg.naturalWidth == w) {
            p = 1;
            o = \'yes\';
            }
        z++;
        }
return o;

}


function check(e,i) {


        if( e == i ){

             if (document.getElementById(\'myss\') != null) {

    //now we need to make sure each image is fully loaded
    for(i=0; i<=myArray.length; i++){

        p=0;
        z=0;

        myCheck[i] = checkimg(myArray[i], myWidth[i]);


    }//end foreach

    if (myCheck.join(\'\') == \'yesyesyesyesyesyesyesyes\') {

    document.getElementById(\'myss\').innerHTML = \'<embed src=\"RectangleSlideshow.swf\" width=\"1028px\" height=\"324px\"></embed>\';

        }
    }

        };
    }