图片自动缩放

 <img src='404.png' onload='AutoResizeImage(195,140,this)'  />

function AutoResizeImage(maxWidth,maxHeight,objImg){
	var img = new Image();
	img.src = objImg.src;
	var hRatio;
	var wRatio;
	var Ratio = 1;
	var w = img.width;
	var h = img.height;
	wRatio = maxWidth / w;
	hRatio = maxHeight / h;
	if (maxWidth ==0 && maxHeight==0){
	Ratio = 1;
	}else if (maxWidth==0){//
	if (hRatio<1) Ratio = hRatio;
	}else if (maxHeight==0){
	if (wRatio<1) Ratio = wRatio;
	}else if (wRatio<1 || hRatio<1){
	Ratio = (wRatio<=hRatio?wRatio:hRatio);
	}
	if (Ratio<1){
	w = w * Ratio;
	h = h * Ratio;
	}
	objImg.height = h;
	objImg.width = w;
}