CSS自动控制图片大小的代码

img {  
max-width: 800px;  
height: auto;  
} 

p img{
max-width: 550px;
width: expression(this.width > 550 ? "550px" : true);
height: auto;
}

//  方法：setSelectReadOnly  用于设定极select控件ReadOnly, 
//这个一个模拟只读不是真的只读 
//使用了onbeforeactivate,onfocus,onmouseover,onmouseout事件 
//示例：< img src='img.jpg' onload='ImgAutoSize(ImgD,FitWidth,FitHeight)' > ; 
//  create by sl  
// --------------------------------------------------- 
function ImgAutoSize(imgD,FitWidth,FitHeight)  
{ 
var image1=new Image();  
image1.onload = function () 
{ 
if(this.width>0 && this.height>0)  
{  
if(this.width/this.height>= FitWidth/FitHeight)  
{  
if(this.width>FitWidth)  
{  
imgD.width=FitWidth;  
imgD.height=(this.height*FitWidth)/this.width;  
}  
else  
{  
imgD.width=this.width;  
imgD.height=this.height;  
}  
}  
else  
{  
if(this.height>FitHeight)  
{  
imgD.height=FitHeight;  
imgD.width=(this.width*FitHeight)/this.height;  
}  
else  
{  
imgD.width=this.width;  
imgD.height=this.height;  
}  
}  
} 
image1 = null; 
}

image1.src=imgD.src;  
imgD.style.cursor = 'hand'; 
imgD.onclick= function(){openWin(this.src,'imgphoto',600,400)}; 
imgD.title = "点击在新窗口中查看原图"; 
}