JS图片按比例压缩-优快云博客

本文链接：https://blog.youkuaiyun.com/iteye_19263/article/details/82065578
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<title>最新javascript自动按比例显示图片，按比例压缩图片显示</title>   
<script type="text/javascript">   
function AutoResizeImage(maxWidth,maxHeight,objImg){    
if (typeof(objImg)=='string'){    
objImg = $(objImg);    
}    
var img = new Image();    
img.onload = function(){    
var hRatio;    
var wRatio;    
var Ratio = 1;    
var w = img.width;    
var h = img.height;    
wRatio = maxWidth / w;    
hRatio = maxHeight / h;    
wRatio = wRatio>1?1:wRatio;    
hRatio = hRatio>1?1:hRatio;    
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 {    
Ratio = (wRatio<=hRatio?wRatio:hRatio);    
}    
if (Ratio<1){    
w = w * Ratio;    
h = h * Ratio;    
}    
objImg.height = h;    
objImg.width = w;    
this.onload = function(){}    
}    
img.src = objImg.src;    
}    
</script>   
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<br />   
原图显示（534 X 800）<br />   
οnlοad="AutoResizeImage(0,0,this)<br />   
<a href="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" target="_blank"> 
<img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" οnlοad="AutoResizeImage(0,0,this)" alt="534 X 800"/></a><br/><br />   
1.按宽度250压缩,不限制高度 按比例压缩<br />   
οnlοad="AutoResizeImage(250,0,this)"<br />   
<a href="http://blog.youkuaiyun.com/feng_sundy/archive/2008/06/19/2566028.aspx" target="_blank"> 
<img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" οnlοad="AutoResizeImage(250,0,this)"  alt="250 X 374"/></a><br /><br />   
2.按高度250压缩,不限制宽度 按比例压缩<br />   
οnlοad="AutoResizeImage(0,250,this)"<br />   
<a href="http://blog.youkuaiyun.com/feng_sundy/archive/2008/06/19/2566028.aspx" target="_blank"> 
<img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" οnlοad="AutoResizeImage(0,250,this)"  alt="166 X 250"/></a><br /><br />   
3.按高度250宽度250 按比例压缩<br />   
οnlοad="AutoResizeImage(250,250,this)"<br />   
<a href="http://blog.youkuaiyun.com/feng_sundy/archive/2008/06/19/2566028.aspx" target="_blank"> 
<img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" οnlοad="AutoResizeImage(250,250,this)"  alt="200 X 300"/></a><br /><br />   
4.高宽不等比例压缩 （400 X 512）,此时高度不变，会自动按高度的比例压缩。<br />   
οnlοad="AutoResizeImage(400,512,this)"<br />   
<a href="http://blog.youkuaiyun.com/feng_sundy/archive/2008/06/19/2566028.aspx" target="_blank"> 
<img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" οnlοad="AutoResizeImage(400,512,this)"  alt="341 X 512"/></a><br /><br />   
5.高宽不等比例压缩 （300 X 600）,此时宽度不变，会自动按宽度的比例压缩。<br />   
οnlοad="AutoResizeImage(300,600,this)"<br />   
<a href="http://blog.youkuaiyun.com/feng_sundy/archive/2008/06/19/2566028.aspx" target="_blank"> 
<img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" οnlοad="AutoResizeImage(300,600,this)"  alt="300 X 449"/></a><br /><br />   
6.如果图片本来的高度和宽度小于压缩的最大高度和宽度，则不会拉大显示图片（按原图显示）<br />   
原图444 x 207,压缩为 500 x 600,将保持原图显示<br />   
οnlοad="AutoResizeImage(500,600,this)"<br />   
<a href="http://blog.youkuaiyun.com/feng_sundy/archive/2008/06/19/2566028.aspx" target="_blank"> 
<img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/242776/o_20070410_b7409cd284a0f799a357uePcEFa6ty0X.jpg" border="0" width="0" height="0" οnlοad="AutoResizeImage(500,600,this)"  alt="444 X 207"/></a><br /><br />   
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