JS控制图片显示的大小（图片等比例缩放）
原文地址为：JS控制图片显示的大小（图片等比例缩放）
代码
转载请注明本文地址：JS控制图片显示的大小（图片等比例缩放）
摘自：http://blog.snsgou.com/post-397.html
<!
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=utf-8" />
< 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){
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 >
< br />
原图显示（534 X 800） < br />
onload="AutoResizeImage(0,0,this) < br />
< a href ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(250,0,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(0,250,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(250,250,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(400,512,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(300,600,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(500,600,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/242776/o_20070410_b7409cd284a0f799a357uePcEFa6ty0X.jpg" border ="0" width ="0" height ="0" onload ="AutoResizeImage(500,600,this)" alt ="444 X 207" /></ a >< br />< br />
</ body >
</ html >
< html xmlns ="http://www.w3.org/1999/xhtml" >
< head >
< meta http-equiv ="Content-Type" content ="text/html; charset=utf-8" />
< 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){
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 >
< br />
原图显示（534 X 800） < br />
onload="AutoResizeImage(0,0,this) < br />
< a href ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(250,0,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(0,250,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(250,250,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(400,512,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(300,600,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border ="0" width ="0" height ="0" onload ="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 />
onload="AutoResizeImage(500,600,this)" < br />
< a href ="http://blog.csdn.net/feng_sundy/archive/2008/06/19/2566028.aspx" target ="_blank" >< img src ="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/242776/o_20070410_b7409cd284a0f799a357uePcEFa6ty0X.jpg" border ="0" width ="0" height ="0" onload ="AutoResizeImage(500,600,this)" alt ="444 X 207" /></ a >< br />< br />
</ body >
</ html >
效果图：
转载请注明本文地址：JS控制图片显示的大小（图片等比例缩放）