canvas实现压缩图片的代码示例

// 对图片进行压缩 
 function compress(imgPath) {
 var image = new Image();
 //新建一个img标签（还没嵌入DOM节点) 
 image.src = imgPath;
 image.onload = function() {
 var canvas = document.createElement('canvas');
 var context = canvas.getContext('2d');
 var imageWidth = image.width / 3;
 //压缩后图片的大小 
 var imageHeight = image.height / 3;
 var data = '';
 canvas.width = imageWidth; 
 canvas.height = imageHeight;
 context.drawImage(image, 0, 0, imageWidth, imageHeight);
 data = canvas.toDataURL('image/jpeg')
 //压缩完成 
 $(".srcDiscernImg").attr("src", data);
 console.log("渲染。。");
 }
 }