移动端签字功能

实现移动端用户签名功能

一、html部分

	
验收人签字:


	
	

myCanvas是签字的div，saveImgDiv是保存后回显的div。

二、页面初始化，添加div签字功能

InitThis();

var mousePressed = false;
var lastX, lastY;
var ctx = document.getElementById('myCanvas').getContext("2d");
var c = document.getElementById("myCanvas");
var selected1, selected2;
function InitThis() {
	// 触摸屏
	c.addEventListener('touchstart', function(event) {
		console.log(1)
		if(event.targetTouches.length == 1) {
			event.preventDefault(); // 阻止浏览器默认事件，重要
			mousePressed = true;
			Draw(event.touches[0].pageX - this.offsetLeft, event.touches[0].pageY - this.offsetTop, false);
		}
	}, false);
	c.addEventListener('touchmove', function(event) {
		console.log(2)
		if(event.targetTouches.length == 1) {
			event.preventDefault(); // 阻止浏览器默认事件，重要
			if(mousePressed) { 
				Draw(event.touches[0].pageX - this.offsetLeft, event.touches[0].pageY - this.offsetTop, true);
	
			}
		}
	}, false);
	c.addEventListener('touchend', function(event) {
		console.log(3)
		if(event.targetTouches.length == 1) {
			event.preventDefault(); // 阻止浏览器默认事件，防止手写的时候拖动屏幕，重要
			mousePressed = false;
		}
	}, false);
	// 鼠标
	c.onmousedown = function(event) {
		mousePressed = true;
		Draw(event.pageX - this.offsetLeft, event.pageY - this.offsetTop, false);
	};
	c.onmousemove = function(event) {
		if(mousePressed) {
			Draw(event.pageX - this.offsetLeft, event.pageY - this.offsetTop, true);
		}
	};
	c.onmouseup = function(event) {
		mousePressed = false;
	};
}
	
function Draw(x, y, isDown) {
	if(isDown) {
		ctx.beginPath();
		ctx.strokeStyle = selected2;
		ctx.lineWidth = selected1;
		ctx.lineJoin = "round";
		ctx.moveTo(lastX, lastY);
		ctx.lineTo(x, y);
		ctx.closePath();
		ctx.stroke();
	}
	lastX = x;
	lastY = y;
}

三、获取图片路径放到saveImgDiv里，签字回显逻辑

var file = "http://10.1.31.173:8097/upload/" + iv[0].zjqm + "?v=" + new Date().getTime();

$("#saveImgDiv").append('');

四、保存用户签名，可以放在保存提交成功的回调里

var saveimgs = document.getElementsByClassName("saveimgs")[0];

//保存签名图片
var image = c.toDataURL("image/png");
var ctximg = document.createElement("span");
ctximg.innerHTML = "";
if(saveimgs.getElementsByTagName('span').length >= 1) {
	var span_old = saveimgs.getElementsByTagName("span")[0];
	saveimgs.replaceChild(ctximg,span_old)
} else {
	saveimgs.appendChild(ctximg);
}

效果