HTML5 canvas获取图片

//将图像输出为base64压缩的字符串 默认为image/png

var data = canvas.toDataURL(); // returns "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAMgAAADICAYAAACt..."
//var data = canvas.toDataURL('image/jpeg'); //returns "data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAA..."



//删除字符串前的提示信息 "data:image/png;base64,"

var b64 = data.substring( 22 );

//POST到服务器上，生成图片

$.post( "save.aspx" , { data : b64, name : filename }, function(){

//OK

});