js+canvas实现验证码功能

 
 
 
 
 


 

 

  
  
 
 

 

  

  
  
  
 
 submit
 
 
 

* {
 margin: 0;
 padding: 0;
}

.wrapper {
 width: 345px;
 border: 1px solid #ccc;
 border-radius: 10px;
 padding: 20px 10px;
 margin: 30px 30px;
}

.inputBox {
 width: 345px;
 margin: 0 auto 10px;
 position: relative;
}

.inputBox .inputCaptcha {
 display: inline-block;
 height: 50px;
 width: 86%;
 text-indent: 1em;
 border: 1px solid #ddd;
 border-radius: 5px;
}

.inputBox .captchaIcon {
 display: none;
 position: absolute;
 top: 50%;
 right: 0px;
 margin-top: -16px;
 width: 32px;
 height: 32px;
 background-size: 100% 100%;
}

.errorText {
 width: 345px;
 margin: 0 auto;
 font-size: 12px;
 color: red;
 display: none;
}

.canvasBox {
 width: 345px;
 margin: 10px auto;
 position: relative;
}

#canvasCaptcha {
 border-radius: 10px;
}

.canvasBox .refresh {
 width: 34px;
 height: 34px;
 position: absolute;
 right: 0px;
 top: 50%;
 margin-top: -17px;
 border: 0;
 border-radius: 6px;
 background-image: url('./images/update.png');
 background-size: cover;
}

.captchaSubmit {
 padding: 10px 20px;
 background-color: #62b900;
 border: 0;
 font-size: 20px;
 border-radius: 5px;
 color: #fff;
}

var arr = [0,1,2,3,4,5,6,7,8,9];
for(var i = 65;i <122;i++){
 if(i>90&&i<97){
 continue;
 }
 arr.push(String.fromCharCode(i));
}
//每个验证码可能出现的字母或数字(区分大小写)
var len = arr.length;
//验证码的长度
var canvasStr,value;
//验证码值
function createCanvas(){
 canvasStr = '';
 value = '';
 for(var i =0 ;i <6;i++){
 var a = arr[Math.floor(Math.random()*len)];
 canvasStr += a+' ';
 value += a; 
 }
//canvas
 var oCanvas = document.getElementById('canvasCaptcha');
 var ctx = oCanvas.getContext('2d');
 var w = oCanvas.width;
 var h = oCanvas.height;
 var oImg = new Image();
 oImg.src = './images/bg.jpg';
 oImg.Onload= function(){
 var pattern = ctx.createPattern(oImg,'repeat');
 ctx.fillStyle = pattern;
 ctx.fillRect(0,0,w,h); 
 ctx.fillStyle = '#ccc';
 ctx.textAlign = 'center';
 ctx.fOnt= '46px Roboto Slab';
 ctx.setTransform(1,-0.12,0.2,1,0,12);
 ctx.fillText(canvasStr,w/2,60);
 }
}

createCanvas();

//验证输入的验证码与图中验证码时候相等
function captcha(e){
 if(e == value){
 return true;
 }
 else{
 return false;
 }
}

//点击提交按钮时的结果
function showResult(){
 var inputValue = $('.inputCaptcha').val();
 
 if(inputValue == '' ||inputValue == null || inputValue == 'undefined'){
 $('.errorText').css({display:'inline-block'}).html('验证码不能为空,请重新输入!');
 $('.captchaIcon').css({display:'inline-block',backgroundImage:"url('./images/false.png')"});
 }else{
 var flag = captcha(inputValue);
 if(!flag){
  $('.errorText').css({display:'inline-block'}).html('验证码错误,请重新输入!');
  $('.captchaIcon').css({display:'inline-block',backgroundImage:"url('./images/false.png')"});
 }else{
  $('.captchaIcon').css({display:'inline-block',backgroundImage:"url('./images/true.png')"});
 }
 }
}
$('.captchaSubmit').click(showResult);//提交
$('.refresh').click(createCanvas);//刷新
//点击input框
$('.inputCaptcha').focus(function(){
 $('.errorText').add($('.captchaIcon')).fadeOut(100);
})