纯前端实现加减运算验证码

实现效果

//页面展示

	<template>
		<view class="form-input-item" style="padding:8rpx 22rpx;">
			<input class="form-input" placeholder="请输入验证码" type="text" maxlength="6" confirm-type="next" placeholder-class="placeholder" name="code" v-model="code"></input>	
			<view >
				 <div id="v_container" style="width:220rpx;height:82rpx;"></div>
			</view>
		</view>
	</template>

<script>
	import { gvertify } from '@/common/gvertify'   //引入
	mounted() {
		this.verifyCode = new gvertify('v_container')  
	}

  //提交表单验证
if (this.code) {
	const verifyFlag = this.verifyCode.validate(this.code);
	console.log(verifyFlag);
	if (!verifyFlag) {
	  this.$u.toast('请输入正确的验证码');
	  return false
	} 
  }
</script>

封装的插件

function gvertify(options) { // 创建一个图形验证码对象，接收options对象为参数
  this.options = { // 默认options参数值
    id: 'canvas', // 容器Id
    canvasId: 'verifyCanvas', // canvas的ID
    width: '100%', // 默认canvas宽度
    height: '100%', // 默认canvas高度
    type: 'number', // 图形验证码默认类型blend:数字字母混合类型、number:纯数字、letter:纯字母
    code: ''
  }

  if (Object.prototype.toString.call(options) === '[object Object]') { // 判断传入参数类型
    for (var i in options) { // 根据传入的参数，修改默认参数值
      this.options[i] = options[i]
    }
  } else {
    this.options.id = options
  }

  this.options.numArr = '0,1,2,3,4,5,6,7,8,9'.split(',')
  this.options.letterArr = getAllLetter()

  this._init()
  this.refresh()
}

gvertify.prototype = {
  /** 版本号**/
  version: '1.0.0',

  /** 初始化方法**/
  _init: function() {
    var con = document.getElementById(this.options.id)
    var canvas = document.createElement('canvas')
    // this.options.width = con.offsetWidth > 0 ? con.offsetWidth : '30'
    // this.options.height = con.offsetHeight > 0 ? con.offsetHeight : '30'
    this.options.width = con.offsetWidth
    this.options.height = '40'
    canvas.id = this.options.canvasId
    canvas.width = this.options.width
    canvas.height = this.options.height
    canvas.style.cursor = 'pointer'
    canvas.innerHTML = '您的浏览器版本不支持canvas'
    con.appendChild(canvas)
    var parent = this
    canvas.onclick = function() {
      parent.refresh()
    }
  },

  /** 生成验证码**/
  refresh: function() {
    var canvas = document.getElementById(this.options.canvasId)
    if (canvas.getContext) {
      var ctx = canvas.getContext('2d')
    }
    ctx.textBaseline = 'middle'

    ctx.fillStyle = randomColor(180, 240)
    ctx.fillRect(0, 0, this.options.width, this.options.height)

    if (this.options.type === 'blend') { // 判断验证码类型
      var txtArr = this.options.numArr.concat(this.options.letterArr)
    } else if (this.options.type === 'number') {
      // eslint-disable-next-line no-redeclare
      var txtArr = this.options.numArr
    } else {
      // eslint-disable-next-line no-redeclare
      var txtArr = this.options.letterArr
    }
    this.options.code = []
    for (var i = 1; i <= 3; i++) {
      var txt = txtArr[randomNum(0, txtArr.length)]
      ctx.font = randomNum(this.options.height, this.options.height) + 'px SimHei' // 随机生成字体大小
      ctx.fillStyle = randomColor(50, 160) // 随机生成字体颜色
      ctx.shadowOffsetX = randomNum(-3, 3)
      ctx.shadowOffsetY = randomNum(-3, 3)
      ctx.shadowBlur = randomNum(-3, 3)
      ctx.shadowColor = 'rgba(0, 0, 0, 0.3)'
      var x = this.options.width / 5 * i
      var y = this.options.height / 2
      var deg = randomNum(-30, 30)
      /** 设置旋转角度和坐标原点**/
      ctx.translate(x, y)
      ctx.rotate(deg * Math.PI / 180)
	  
	  // 中间符号
      if (i === 2) {
        const index = randomNum(0, 3)
        const fuhao = ['+', '-', '*'][index]
        console.log(fuhao)
        ctx.fillText(fuhao, 0, 0)
        this.options.code.push(fuhao)
      } else {
        ctx.fillText(txt, 0, 0)
        this.options.code.push(Number(txt))
      }
      /** 恢复旋转角度和坐标原点**/
      ctx.rotate(-deg * Math.PI / 180)
      ctx.translate(-x, -y)
    }
    /** 绘制干扰线**/
    // eslint-disable-next-line no-redeclare
    for (var i = 0; i < 4; i++) {
      ctx.strokeStyle = randomColor(40, 180)
      ctx.beginPath()
      ctx.moveTo(randomNum(0, this.options.width), randomNum(0, this.options.height))
      ctx.lineTo(randomNum(0, this.options.width), randomNum(0, this.options.height))
      ctx.stroke()
    }
    /** 绘制干扰点**/
    // eslint-disable-next-line no-redeclare
    for (var i = 0; i < this.options.width / 4; i++) {
      ctx.fillStyle = randomColor(0, 255)
      ctx.beginPath()
      ctx.arc(randomNum(0, this.options.width), randomNum(0, this.options.height), 1, 0, 2 * Math.PI)
      ctx.fill()
    }
  },

  /** 验证验证码**/
  validate: function(code) {
    // eslint-disable-next-line no-redeclare
    var code = Number(code)

    var v_code
    if (this.options.code[1] === '-') {
      v_code = this.options.code[0] - this.options.code[2]
    } else if (this.options.code[1] === '+') {
      v_code = this.options.code[0] + this.options.code[2]
    } else if (this.options.code[1] === '*') {
      v_code = this.options.code[0] * this.options.code[2]
    }
    console.log(this.options.code, v_code, code)
    if (code === v_code) {
      return true
    } else {
      return false
    }
  }
}
/** 生成字母数组**/
function getAllLetter() {
  var letterStr = 'a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z'
  return letterStr.split(',')
}
/** 生成一个随机数**/
function randomNum(min, max) {
  return Math.floor(Math.random() * (max - min) + min)
}
/** 生成一个随机色**/
function randomColor(min, max) {
  var r = randomNum(min, max)
  var g = randomNum(min, max)
  var b = randomNum(min, max)
  return 'rgb(' + r + ',' + g + ',' + b + ')'
}

export {
  gvertify
}