http://www.jsjxmhw.com/Script/Html.js

1/*按比例生成缩略图*/
2function DrawImage(ImgD,W,H){ 
3  var flag=false; 
4  var image=new Image(); 
5  image.src=ImgD.src; 
6  if(image.width>0 && image.height>0){ 
7    flag=true; 
8    if(image.width/image.height>= W/H){ 
9      if(image.width>W){
10        ImgD.width=W; 
11        ImgD.height=(image.height*H)/image.width; 
12      }
13	  else{ 
14        ImgD.width=image.width;
15        ImgD.height=image.height; 
16      } 
17      ImgD.alt= ""; 
18    } 
19    else{ 
20      if(image.height>H){
21        ImgD.height=H; 
22        ImgD.width=(image.width*W)/image.height; 
23      }
24	  else{ 
25        ImgD.width=image.width;
26        ImgD.height=image.height; 
27      } 
28      ImgD.alt=""; 
29    } 
30  }
31}