第一步：环境准备
jquery、jSignature
第二步：demo编写
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<title>手写板签名demo</title>
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
<meta charset="UTF-8">
<meta name="description" content="overview & stats" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" />
</head>
<body>
<p id="signature"></p>
<p style="text-align: center">
<b style="color: red">请按着鼠标写字签名。</b>
</p>
<input type="button" value="保存" id="yes"/>
<input type="button" value="下载" id="download"/>
<input type="button" value="重写" id="reset"/>
<p id="someelement"></p>
<script src="jquery-2.0.3.min.js"></script>
<!--[if lt IE 9]>
<script src="jSignature/flashcanvas.js"></script>
<![endif]-->
<script src="jSignature/jSignature.min.js"></script>
<script>
$(function() {
var $sigp = $("#signature");
$sigp.jSignature(); // 初始化jSignature插件.
$("#yes").click(function(){
//将画布内容转换为图片
var datapair = $sigp.jSignature("getData", "image");
var i = new Image();
i.src = "data:" + datapair[0] + "," + datapair[1];
$(i).appendTo($("#someelement")); // append the image (SVG) to DOM.
});
//datapair = $sigp.jSignature("getData","base30");
//$sigp.jSignature("setData", "data:" + datapair.join(","));
$("#download").click(function(){
downloadFile("a.png", convertBaseUrlToBlob($("img").attr("src")));
});
$("#reset").click(function(){
$sigp.jSignature("reset"); //重置画布，可以进行重新作画.
$("#someelement").html("");
});
});
function downloadFile(fileName, blob){
var aLink = document.createElement('a');
var evt = document.createEvent("HTMLEvents");
evt.initEvent("click", false, false);//initEvent 不加后两个参数在FF下会报错, 感谢 Barret Lee 的反馈
aLink.download = fileName;
aLink.href = URL.createObjectURL(blob);
aLink.dispatchEvent(evt);
}
/**
* 将以base的图片url数据转换为Blob
* @param urlData
* 用url方式表示的base图片数据
*/
function convertBaseUrlToBlob(urlData){
var bytes=window.atob(urlData.split(',')[1]); //去掉url的头，并转换为byte
//处理异常,将ascii码小于0的转换为大于0
var ab = new ArrayBuffer(bytes.length);
var ia = new Uint8Array(ab);
for (var i = 0; i < bytes.length; i++) {
ia[i] = bytes.charCodeAt(i);
}
return new Blob( [ab] , {type : 'image/png'});
}
</script>
</body>
</html>第三步：测试
经测试，成功！