利用獲取圖片尺寸與圖片大小（高度與寬度)要注意一點的是要等 圖片載入完成後才能js 獲取圖片寬度與高度的，所以要判斷在readystate=="complete"的狀態下獲取大小,如果是利用file上傳的話， 每次都要點擊清除image=new image(); imgage.width與高度哦。
<!doctype html public "-//w3c//dtd xhtml 1.0 transitional//en" "HTTP://www.w3.org/tr/xhtml1/dtd/ xhtml1-transitional.dtd">
<html xmlns="HTTP://www.w3.org/1999/xhtml">
<head>
<meta HTTP-equiv="content-type" content="text/html; charset=gb2312" />
<title>js獲取圖片尺寸與圖片大小（高度與寬度)</title>
<script>
function checkimg(img)
{
var message="";
var maxwidth=1;//設置圖片寬度界限
var maxheight=1;//設置圖片高度界限
if(img.readystate!="complete"){
return false;//確保圖片完全載入
}
if(img.offsetheight>maxheight) message+="r高度超額："+img.offsetheight;
if(img.offsetwidth>maxwidth) message+="r寬度超額："+img.offsetwidth;
if(message!="") alert(message);
}
</script>
</head>
<body>
<img src="images/frequency.gif" border=0 id="img1" onload="checkimg(this);" >
<br> <input id=inp type="file" onpropertychange="img1.src=this.value;" >
</body>
圖片載入完成後才能成功獲取圖片大小，所以要判斷在readystate=="complete"的狀態下獲取大小
測試代碼二
<script>
function qford_getimagesize(filepath)
{
var imgsize={
width:0,
height:0
};
image=new image();
image.src=filepath;
imgsize.width =image .width;
imgsize .height=image .height;
return imgsize;
}
</script>
js獲取圖片尺寸函數測試：</br>
<img src="test.jpg" mce_src="test.jpg" />
< script type="text/網頁特效"><!--
var a=qford_getimagesize("test.jpg");
alert(' 寬：'+a.width +' 高：'+a.height);
</script>
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