Javascript實現圖片按比例縮放的函數

javascript|函數

　　圖片按比例縮放函數：

<script language="JavaScript">
<!--
//圖片按比例縮放
var flag=false;
function DrawImage(ImgD){
var image=new Image();
var iwidth = 150; //定義允許圖片寬度
var iheight = 100; //定義允許圖片高度
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;
}
}
}
//調用：<img src="圖片" >
//-->
</script>

　　樣本如下：

<script language="JavaScript"><!--//圖片按比例縮放var flag=false;function DrawImage(ImgD){var image=new Image();var iwidth = 150; //定義允許圖片寬度var iheight = 100; //定義允許圖片高度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;}}} //調用：<img src="圖片" >//--></script><img src="/UploadPic/2007-7/200777172211913.jpg" >