js将图片转化为base64

参考地址： http://www.cnblogs.com/mr-wuxiansheng/p/6931077.html

var img = "imgurl";//imgurl 就是你的图片路径  
function getBase64Image(img) {  
     var canvas = document.createElement("canvas");  
     canvas.width = img.width;  
     canvas.height = img.height;  
     var ctx = canvas.getContext("2d");  
     ctx.drawImage(img, 0, 0, img.width, img.height);  
     var ext = img.src.substring(img.src.lastIndexOf(".")+1).toLowerCase();  
     var dataURL = canvas.toDataURL("image/"+ext);  
     return dataURL;