不知道哪天看到的一个朋友圈里面有发的什么什么免费教签名之类的，就看了下SVG，做这功能还不错。
主要用到的几个属性，需要自行百度一下，不详说 stroke-dashoffset , stroke-dasharray 主要这两个。
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="800" width="800">
<path d="m40.995594,214.000244c0,0 1.000015,0 2.000034,0c3.000053,0 7.000122,0 16.000282,0c9.00016,0 21.111244,0.704391 36.000641,-2.000031c13.127121,-2.384338 23.844788,-5.45723 35.00061,-9.000168c10.867096,-3.451233 23.077621,-6.812241 33.000595,-11.000183c9.07399,-3.829636 14.436508,-7.439819 21.000366,-13.000229c5.395462,-4.570648 8.579849,-11.157074 11.000198,-17.000305c2.567169,-6.197678 5.000092,-12.000214 5.000092,-20.000351c0,-4.000076 0,-9.000168 0,-13.000229c0,-4.000076 -0.613846,-8.297142 -3.000061,-11.000198c-1.479858,-1.676361 -1.823776,-4.486343 -4.000076,-5.000092c-0.973267,-0.229752 -3.000046,0 -5.000076,0c-4.000076,0 -7.291977,-1.101685 -13.000229,1.000015c-5.471954,2.014694 -11.593079,6.106377 -18.00032,11.000198c-3.371719,2.575302 -9.195923,10.891907 -13.000229,18.00032c-3.165375,5.914566 -3.391785,14.1875 -5.000092,21.000366c-1.54126,6.52887 -3.000061,10.000183 -3.000061,17.000305c0,5.000092 0.498749,10.946915 1.000031,18.00032c0.425354,5.985016 0.054459,11.090424 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-2.000031,1.000015 -4.000061,2.000031c-2.000031,1.000015 -3.000061,2.000031 -6.000092,2.000031l-4.000092,2.000046" id="svg_1" class="q12" stroke-width="1.5" stroke="#000" fill="none"/>
</svg>
上面的代码可忽略，主要是用SVG画出的一个文字，怎么让这个文字动起来，往下看
样式部分：
<style type="text/css"> .active{ -webkit-animation: go 10s infinite; } @-webkit-keyframes go{ form{ stroke-dashoffset: 10000; } to{ stroke-dashoffset: 0; } } </style>
JS部分
<script type="text/javascript">
var p = document.querySelector("#svg_1");
var l = p.getTotalLength();
$('#svg_1').css({
strokeDashoffset: l,
strokeDasharray: l,
stroke:"red",
strokeWidth:"10px"
})
$(document).on("click",function(){
debugger
p.className.baseVal = "active";
})
</script>
好啦，自己跑一跑吧
对了对了！！！ 附送一个svg 在线编辑工具 http://editor.method.ac/
另外再给一个网站，里面东西不错 http://www.yyyweb.com/