js将html生成为图片，并保存在本地

<p class="tongxingzheng_bg">
 <p class="tongxingcard">
 <p class="titlebar">访客通行证</p>
 <p class="tx_content">
 <p class="wl_logo"><img src="$!webPath/resources/images/logo.png" ></p>
 <p class="xinxi">
 <p class="name">$!{data.name}</p>
 <p class="tongxingma">
 <span class="text">通行码：</span>
 <span class="code">$!{data.number}</span>
 </p>
 </p>
 </p>
 <p class="itemLine">
 <span class="mudi">目的地：</span>
 <span class="address">$!{data.property}</span>
 </p>
 <p class="itemLine">
 <p class="item">
 <p class="text">人数：</p>
 <p class="amount">$!{data.persons}</p>
 </p>
 <p class="item">
 <p class="text">是否有车：</p>
 <p class="amount">#if($!data.haveCar)有#else 无#end</p>
 </p>
 </p>
 <p class="itemLine">
 <span class="youxiaoshijian">有效时间：</span>
 <span class="date">$!{data.visitingTime}</span>
 <p class="tishi">当天有效</p>
 </p>
 <p class="bottom">进入园区时，出示此通行证给保安</p>
 </p>
 <p class="bottomline">
 <p class="item" id="saveImg" style="width: 100%;">保存图片</p>
 
 </p>
</p>

$(function(){
	$("#saveImg").click(function(){
	 html2canvas($(".tongxingzheng_bg")).then(function(canvas) {
	 var imgUri = canvas.toDataURL("image/png").replace("image/png", "image/octet-stream"); // 获取生成的图片的url
	 window.location.href= imgUri; // 下载图片
	 });
	 });
});