js+canvas实现验证码功能
程序员文章站
2022-05-16 13:16:09
刚刚开始接触canvas，写个验证码小功能练练手，实现效果图如下：
主要代码如下:
html
刚刚开始接触canvas，写个验证码小功能练练手，实现效果图如下：
主要代码如下:
html
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="x-ua-compatible" content="ie=edge">
<title>document</title>
<link rel="stylesheet" href="index.css" rel="external nofollow" >
</head>
<body>
<div class="wrapper">
<div class="inputbox">
<input type="text" class = 'inputcaptcha' placeholder = "请输入验证码">
<span class="captchaicon"></span>
</div>
<p class="errortext"></p>
<div class="canvasbox">
<div class="imagebox">
<canvas width =300 height=80 id = 'canvascaptcha'></canvas>
<input type="button" class='refresh'>
</div>
</div>
<button class="captchasubmit">submit</button>
</div>
<script src='./jquery.js'></script>
<script src = './index.js'></script>
</body>
</html>
css
* {
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;
}
js
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);
})
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。
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