html2canvas将Html5转换为图片并下载到本地，纯JS实现

首先引入html2canvas.js

<script type="text/javascript" src="http://html2canvas.hertzen.com/dist/html2canvas.js"></script>

然后是文件本地保存并重命名的一段函数，最后事件函数处理就可以了

/**
             * 在本地进行文件保存
             * @param  {String} data     要保存到本地的图片数据
             * @param  {String} filename 文件名
             */
            var saveFile = function(data, filename){
                var save_link = document.createElementNS('http://www.w3.org/1999/xhtml', 'a');
                save_link.href = data;
                save_link.download = filename;

                var event = document.createEvent('MouseEvents');
                event.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
                save_link.dispatchEvent(event);
            };

function exportToPic() {        
                html2canvas(
                    document.body,
                    {
                        onrendered: function (canvas) {                         
                            var pageData = canvas.toDataURL('image/jpeg', 1.0);

							console.log(pageData)
                            //window.location=(pageData.replace("image/jpeg", "image/octet-stream"));
							saveFile(pageData.replace("image/jpeg", "image/octet-stream"),new Date().getTime()+".jpeg");
                            
                    })
            }