function SetSize(obj, width, height)

{

myImage = new Image();

myImage.src = obj.src;

if (myImage.width>0 && myImage.height>0)

{

var rate = 1;

if (myImage.width>width || myImage.height>height)

{

if (width/myImage.width<height/myImage.height)

{

rate = width/myImage.width;

}

else

{

rate = height/myImage.height;

}

}

if (window.navigator.appName == "Microsoft Internet Explorer")

{

obj.style.zoom = rate;

}

else

{

obj.width = myImage.width*rate;

obj.height = myImage.height*rate;

}

}

} 

用法： 

<img src="img/offer/41936519.jpg" border="0" style="zoom: 0.1" onload="SetSize(this, 80, 60)"/>