Will this actually reload images?

I've written this simple image preloader based on my knowledge of javascript, but I don't know if it will actually load the images before the page is displayed or if it will still load the images.

   function preloadImages(html) {   
for(var i=0;i<document.images.length;i++) {
    img_obj = new Image();
    img_obj.开发者_开发问答src = document.images[i].src;
    if (!img_obj.complete) alert("could not load:" + img_obj.src);
    else continue;
}   
   $("#pad").fadeIn(200);
   return true;
}

In addition, is it correct the way I preload the images?

To load the image the image needs to have a height/width on the page.

I think most people commonly insert the image into DOM, setting a height, width, making sure display is block. Set an absolute position at -9999px left and top, or something along those lines. The images will be cached for when you need them.

Depending on what you want to do. The js should run onload which is after the page has loaded so I am not sure you really get any benefit. (http://dean.edwards.name/weblog/2005/02/order-of-events/)

You can do preloading using CSS.