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; }