js 控制图片大小核心讲解

控制图片大小的方法有很多，在本文将为大家详细介绍下使用js实现缩放图片，核心代码如下，感兴趣的朋友可以参考下

缩放图片脚本分享

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<title>js 控制图片大小-www.jbxue.com</title>

<meta name="Generator" content="EditPlus">

<meta name="Author" content="">

<meta name="Keywords" content="">

<meta name="Description" content="">

<script>

function AutoResizeImage(maxWidth,maxHeight){

var objImg = document.getElementById("operImg");

var img = new Image();

img.src = objImg.src;

var hRatio;

var wRatio;

var Ratio = 1;

var w = img.width;

var h = img.height;

wRatio = maxWidth / w;

hRatio = maxHeight / h;

if (maxWidth ==0 && maxHeight==0){

Ratio = 1;

}else if (maxWidth==0){//

if (hRatio<1) Ratio = hRatio;

}else if (maxHeight==0){

if (wRatio<1) Ratio = wRatio;

}else if (wRatio<1 || hRatio<1){

Ratio = (wRatio<=hRatio?wRatio:hRatio);

}

if (Ratio<1){

w = w * Ratio;

h = h * Ratio;

}

objImg.height = h;

objImg.width = w;

}

</script> 

</head> 

<body> 

<img src="1111.jpg" border="0" alt="534 X 800" id="operImg"/> 

<input type="button" value="缩放至宽100px，等比例压缩" onclick="AutoResizeImage(100,0)"/> 

<input type="button" value="缩放至300px，等比例压缩" onclick="AutoResizeImage(300,0)"/> 

<input type="button" value="原图" onclick="AutoResizeImage(0,0)"/>

</body>

</html>

重点js:

function AutoResizeImage(maxWidth,maxHeight){

var objImg = document.getElementById("operImg");

var img = new Image();

img.src = objImg.src;

var hRatio;

var wRatio;

var Ratio = 1;

var w = img.width;

var h = img.height;

wRatio = maxWidth / w;

hRatio = maxHeight / h;

if (maxWidth ==0 && maxHeight==0){

Ratio = 1;

}else if (maxWidth==0){//

if (hRatio<1) Ratio = hRatio;

}else if (maxHeight==0){

if (wRatio<1) Ratio = wRatio;

}else if (wRatio<1 || hRatio<1){

Ratio = (wRatio<=hRatio?wRatio:hRatio);

}

if (Ratio<1){

w = w * Ratio;

h = h * Ratio;

}

objImg.height = h;

objImg.width = w;

}

巴特西

js 控制图片大小核心讲解

最新文章

热门文章