在登入页面，我们往往需要通过输入验证码才能进行登入，那我们下面就详讲一下在vue项目中如何配合element-ui实现这个功能
第一步：自定义一个生产随机验证码的组件，其本质是使用canvas绘制，详细代码如下：
<template> <div> <canvas :width="contentWidth" :height="contentHeight"></canvas> </div> </template> <script> export default { name: 'SIdentify', props: { identifyCode: { type: String, default: '1234' }, fontSizeMin: { type: Number, default: 16 }, fontSizeMax: { type: Number, default: 40 }, backgroundColorMin: { type: Number, default: 180 }, backgroundColorMax: { type: Number, default: 240 }, colorMin: { type: Number, default: 50 }, colorMax: { type: Number, default: 160 }, lineColorMin: { type: Number, default: 40 }, lineColorMax: { type: Number, default: 180 }, dotColorMin: { type: Number, default: 0 }, dotColorMax: { type: Number, default: 255 }, contentWidth: { type: Number, default: 112 }, contentHeight: { type: Number, default: 38 } }, methods: { // 生成一个随机数 randomNum(min, max) { return Math.floor(Math.random() * (max - min) + min) }, // 生成一个随机的颜色 randomColor(min, max) { var r = this.randomNum(min, max) var g = this.randomNum(min, max) var b = this.randomNum(min, max) return 'rgb(' + r + ',' + g + ',' + b + ')' }, drawPic() { var canvas = document.getElementById('s-canvas') var ctx = canvas.getContext('2d') ctx.textBaseline = 'bottom' // 绘制背景 ctx.fillStyle = this.randomColor( this.backgroundColorMin, this.backgroundColorMax ) ctx.fillRect(0, 0, this.contentWidth, this.contentHeight) // 绘制文字 for (let i = 0; i < this.identifyCode.length; i++) { this.drawText(ctx, this.identifyCode[i], i) } this.drawLine(ctx) this.drawDot(ctx) }, drawText(ctx, txt, i) { ctx.fillStyle = this.randomColor(this.colorMin, this.colorMax) ctx.font = this.randomNum(this.fontSizeMin, this.fontSizeMax) + 'px SimHei' var x = (i + 1) * (this.contentWidth / (this.identifyCode.length + 1)) var y = this.randomNum(this.fontSizeMax, this.contentHeight - 5) var deg = this.randomNum(-45, 45) // 修改坐标原点和旋转角度 ctx.translate(x, y) ctx.rotate(deg * Math.PI / 180) ctx.fillText(txt, 0, 0) // 恢复坐标原点和旋转角度 ctx.rotate(-deg * Math.PI / 180) ctx.translate(-x, -y) }, drawLine(ctx) { // 绘制干扰线 for (let i = 0; i < 8; i++) { ctx.strokeStyle = this.randomColor( this.lineColorMin, this.lineColorMax ) ctx.beginPath() ctx.moveTo( this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight) ) ctx.lineTo( this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight) ) ctx.stroke() } }, drawDot(ctx) { // 绘制干扰点 for (let i = 0; i < 100; i++) { ctx.fillStyle = this.randomColor(0, 255) ctx.beginPath() ctx.arc( this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight), 1, 0, 2 * Math.PI ) ctx.fill() } } }, watch: { identifyCode() { this.drawPic() } }, mounted() { this.drawPic() } } </script>
第二步：使用该组件：
我们首先新建一个vue组件，在该组件进行布局，其中还包括用户名和密码的验证（这只是前端的简单验证，真实项目中还需要请求登入接口进行后端验证）
<template> <el-form status-icon :rules="loginRules" ref="loginForm" :model="loginForm" label-width="0"> <el-form-item prop="username"> <el-input size="small" @keyup.enter.native="handleLogin" v-model="loginForm.username" auto-complete="off" placeholder="请输入用户名"> <i slot="prefix"></i> </el-input> </el-form-item> <el-form-item prop="password"> <el-input size="small" @keyup.enter.native="handleLogin" :type="passwordType" v-model="loginForm.password" auto-complete="off" placeholder="请输入密码"> <i :style="fontstyle" slot="suffix" @click="showPassword"></i> <i slot="prefix"></i> </el-input> </el-form-item> <el-form-item prop="verifycode"> <!-- 注意：prop与input绑定的值一定要一致，否则验证规则中的value会报undefined，因为value即为绑定的input输入值 --> <el-input v-model="loginForm.verifycode" placeholder="请输入验证码"></el-input> </el-form-item> <el-form-item> <div> <div @click="refreshCode"> <s-identify :identifyCode="identifyCode"></s-identify> </div> <el-button @click="refreshCode" type='text'>看不清，换一张</el-button> </div> </el-form-item> <el-checkbox v-model="checked">记住账号</el-checkbox> <el-form-item> <el-button type="primary" size="small" @click.native.prevent="handleLogin">登录</el-button> </el-form-item> </el-form> </template>
第三步：生产随机码与进行登入验证