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<meta http-equiv="Content-Type" content="text/html; charset=gbk" />
<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,wRatio,Ratio = 1,w = img.width, 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>
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<br />原图显示（534 X 800）
<br />onload="AutoResizeImage(0,0,this)"
<br />
<img onload="AutoResizeImage(0,0,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" alt="534 X 800"/>
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<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 />
<img onload="AutoResizeImage(250,0,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" alt="250 X 374"/>
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<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 />
<img onload="AutoResizeImage(0,250,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" alt="166 X 250"/>
<br />
<br />3.按高度250宽度250 按比例压缩
<br />onload="AutoResizeImage(250,250,this)"
<br />
<img onload="AutoResizeImage(250,250,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" alt="200 X 300"/>
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<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 />
<img onload="AutoResizeImage(400,512,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" alt="341 X 512"/>
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<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 />
<img onload="AutoResizeImage(300,600,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" alt="300 X 449"/>
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<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 />
<img onload="AutoResizeImage(500,600,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/242776/o_20070410_b7409cd284a0f799a357uePcEFa6ty0X.jpg" border="0" width="0" height="0"/>
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