JavaScript

//图片按比例缩放var flag=false;function DrawImage(ImgD,iwidth,iheight){ //参数(图片,允许的宽度,允许的高度) var image=new Image(); image.src=ImgD.src; if(image.width>0 && image.height>0){ flag=true; if(image.width/image.height>= iwidth/iheight){ if(image.width>iwidth){ ImgD.width=iwidth; ImgD.height=(image.height*iwidth)/image.width; }else{ ImgD.width=image.width; ImgD.height=image.height; } ImgD.alt=image.width+"×"+image.height; } else{ if(image.height>iheight){ ImgD.height=iheight; ImgD.width=(image.width*iheight)/image.height; }else{ ImgD.width=image.width; ImgD.height=image.height; } ImgD.alt=image.width+"×"+image.height; } }} 

html

<img src="images/toplogo.gif" onload="javascript:DrawImage(this,100,100)">