怎么在html5中使用canvas手写签名？很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
window.onload = function() { new lineCanvas({ el: document.getElementById("canvas"),//绘制canvas的父级div clearEl: document.getElementById("clearCanvas"),//清除按钮 saveEl: document.getElementById("saveCanvas"),//保存按钮 // linewidth:1,//线条粗细，选填 // color:"black",//线条颜色，选填 // background:"#ffffff"//线条背景，选填 });};function lineCanvas(obj) { this.linewidth = 1; this.color = "#000000"; this.background = "#ffffff"; for (var i in obj) { this[i] = obj[i]; }; this.canvas = document.createElement("canvas"); this.el.appendChild(this.canvas); this.cxt = this.canvas.getContext("2d"); this.canvas.width = this.el.clientWidth; this.canvas.height = this.el.clientHeight; this.cxt.fillStyle = this.background; this.cxt.fillRect(0, 0, this.canvas.width, this.canvas.width); this.cxt.strokeStyle = this.color; this.cxt.lineWidth = this.linewidth; this.cxt.lineCap = "round"; //开始绘制 this.canvas.addEventListener("touchstart", function(e) { this.cxt.beginPath(); this.cxt.moveTo(e.changedTouches[0].pageX, e.changedTouches[0].pageY); }.bind(this), false); //绘制中 this.canvas.addEventListener("touchmove", function(e) { this.cxt.lineTo(e.changedTouches[0].pageX, e.changedTouches[0].pageY); this.cxt.stroke(); }.bind(this), false); //结束绘制 this.canvas.addEventListener("touchend", function() { this.cxt.closePath(); }.bind(this), false); //清除画布 this.clearEl.addEventListener("click", function() { this.cxt.clearRect(0, 0, this.canvas.width, this.canvas.height); }.bind(this), false); //保存图片，直接转base64 this.saveEl.addEventListener("click", function() { var imgBase64 = this.canvas.toDataURL(); console.log(imgBase64); }.bind(this), false);};这是效果图：
附上html和css
<div id="canvas"> <p id="clearCanvas">清除</p> <p id="saveCanvas">保存</p></div>html,body{ width: 100%; height: 100%;}#canvas{ width: 100%; height: 100%; position: relative;}#canvas canvas{ display: block;}#clearCanvas{ width: 50%; height: 40px; line-height: 40px; text-align: center; position: absolute; bottom: 0; left: 0; border: 1px solid #DEDEDE; z-index: 1;}#saveCanvas{ width: 50%; height: 40px; line-height: 40px; text-align: center; position: absolute; bottom: 0; right: 0; border: 1px solid #DEDEDE; z-index: 1;}看完上述内容是否对您有帮助呢？如果还想对相关知识有进一步的了解或阅读更多相关文章，请关注编程网行业资讯频道，感谢您对编程网的支持。
