我们从自然手上收到的最大礼物就是生命。我必须拼命的奔跑我知道有很多人等着看我狼狈跌倒的下场嘲笑我不自量力
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" rel="nofollow noopener noreferrer" 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);
})
本文js+canvas实现验证码功能到此结束。人生的路漫长而多彩，就像在天边的大海上航行，有时会风平浪静，行驶顺利;而有时却会是惊涛骇浪，行驶艰难。但只要我们心中的灯不熄灭，就能沿着自己的航线继续航行。谢谢大家支持！