JavaScript编写带旋转+线条干扰的验证码脚本实例
发布于 2017-03-30 05:06:48 | 269 次阅读 | 评论: 0 | 来源: 网友投递
这里有新鲜出炉的Javascript教程，程序狗速度看过来！
JavaScript客户端脚本语言
Javascript 是一种由Netscape的LiveScript发展而来的原型化继承的基于对象的动态类型的区分大小写的客户端脚本语言，主要目的是为了解决服务器端语言，比如Perl，遗留的速度问题，为客户提供更流畅的浏览效果。
除了普通的可点击更换的四位验证码实现,我们这里还展示了更进一步的JavaScript编写带旋转+线条干扰的验证码脚本实例,需要的朋友可以参考下
基础版
从我们平时上网的经验来看,验证码一般是四位,由数字和字母组成。
那么接下来楼主将带领大家一步步用JavaScript做出一个验证码脚本!
先给出成品，方便大家理解：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<style>
#securityCode{
background-color: #008000;
width:70px;
height:30px;
font-family: '楷体', serif;
font-size: 20px;
color:white;
}
</style>
<script language="JavaScript" type="text/javascript">
function createCode(){
var code=new Array(0,1,2,3,4,5,6,7,8,9,
'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');
var codeNumber;
securityCode="";//全局变量,方便后续验证
for(var i=0;i<4;i++){
codeNumber=Math.floor(Math.random()*36);
securityCode+=code[codeNumber];
}
document.getElementById("securityCode").value=securityCode;
}
function verify(){
var enterCode=document.getElementById("enterCode").value;
if(enterCode.toUpperCase()==securityCode){
alert("输入正确,通过验证!");
}
else{
enterCode.value="";
createCode();
}
}
</script>
<title>Jizhen Tan</title>
</head>
<body onLoad="checkCookie()" >
<input type="text" id="enterCode"><br/>
<input type="button" id="securityCode" onclick="createCode()">
<a href="###" onclick="createCode()">看不清楚</a><br/>
<input type="button" style="background-color: #0099FF; font-size: 20px;"value="验证" onclick="verify()">
</body>
</html>
1.既然是四位验证码,我们的思路就要打开一些了,首先我们需要一个数组来储存字母和数字。
var code=new Array(0,1,2,3,4,5,6,7,8,9,
'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');
2.然后我们需要让它随机显示数组中的元素，这里我们建立一个codeNumber变量来随机显示的数字,但我们需要的是四位验证码，而现在数组中的元素都是单个的，怎么办呢？简单！我们再建立一个securityCode变量来储存数组中的元素不就得了。代码如下：
var codeNumber;
securityCode="";//全局变量,方便后续验证
for(var i=0;i<4;i++){
codeNumber=Math.floor(Math.random()*36);
securityCode+=code[codeNumber];
}
可以看出此时securityNumber变量储存的就是一个四位随机验证码
3.好了，经过简单的两步，我们就得到了四位验证码。我们将它放在一个createCode函数中。
function createCode(){
var code=new Array(0,1,2,3,4,5,6,7,8,9,
'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');
var codeNumber;
securityCode="";//全局变量,方便后续验证
for(var i=0;i<4;i++){
codeNumber=Math.floor(Math.random()*36);
securityCode+=code[codeNumber];
}
document.getElementById("securityCode").value=securityCode;
}
4.接下来我们创建一个验证机制：
function verify(){
var enterCode=document.getElementById("enterCode").value;
if(enterCode.toUpperCase()==securityCode){
alert("输入正确,通过验证!");
}
else{
enterCode.value="";
createCode();
}
}
5.小小修饰下验证码：
<style>
#securityCode{
background-color: #008000;
width:70px;
height:30px;
font-family: '楷体', serif;
font-size: 20px;
color:white;
}
</style>
进阶：进一步阻止机器人的高级技巧
接触的大部分项目中，验证码一直都是后台干的事，这两天正好有一个页面需要验证码，第时间想着后台实现，但突然转念一想大部分项目貌似对安全性要求不是很高，又要求有点阻止机器人的技巧，于是就用前端写了一个验证码。并利用CSS3的transform属性里的rotate设置旋转，再随机弄点干扰线，最后为了在所有DOM节点的上边加一层opacity=0的DIV，一个前端验证码就出来了。
vCode代码：
(function(){
var randstr = function(length){
var key = {
str : [
'a','b','c','d','e','f','g','h','i','j','k','l','m',
'o','p','q','r','s','t','x','u','v','y','z','w','n',
'0','1','2','3','4','5','6','7','8','9'
],
randint : function(n,m){
var c = m-n+1;
var num = Math.random() * c + n;
return Math.floor(num);
},
randStr : function(){
var _this = this;
var leng = _this.str.length - 1;
var randkey = _this.randint(0, leng);
return _this.str[randkey];
},
create : function(len){
var _this = this;
var l = len || 10;
var str = '';
for(var i = 0 ; i<l ; i++){
str += _this.randStr();
}
return str;
}
};
length = length ? length : 10;
return key.create(length);
};
var randint = function(n,m){
var c = m-n+1;
var num = Math.random() * c + n;
return Math.floor(num);
};
var vCode = function(dom, options){
this.codeDoms = [];
this.lineDoms = [];
this.initOptions(options);
this.dom = dom;
this.init();
this.addEvent();
this.update();
this.mask();
};
vCode.prototype.init = function(){
this.dom.style.position = "relative";
this.dom.style.overflow = "hidden";
this.dom.style.cursor = "pointer";
this.dom.title = "点击更换验证码";
this.dom.style.background = this.options.bgColor;
this.w = this.dom.clientWidth;
this.h = this.dom.clientHeight;
this.uW = this.w / this.options.len;
};
vCode.prototype.mask = function(){
var dom = document.createElement("div");
dom.style.cssText = [
"width: 100%",
"height: 100%",
"left: 0",
"top: 0",
"position: absolute",
"cursor: pointer",
"z-index: 9999999"
].join(";");
dom.title = "点击更换验证码";
this.dom.appendChild(dom);
};
vCode.prototype.addEvent = function(){
var _this = this;
_this.dom.addEventListener("click", function(){
_this.update.call(_this);
});
};
vCode.prototype.initOptions = function(options){
var f = function(){
this.len = 4;
this.fontSizeMin = 20;
this.fontSizeMax = 48;
this.colors = [
"green",
"red",
"blue",
"#53da33",
"#AA0000",
"#FFBB00"
];
this.bgColor = "#FFF";
this.fonts = [
"Times New Roman",
"Georgia",
"Serif",
"sans-serif",
"arial",
"tahoma",
"Hiragino Sans GB"
];
this.lines = 8;
this.lineColors = [
"#888888",
"#FF7744",
"#888800",
"#008888"
];
this.lineHeightMin = 1;
this.lineHeightMax = 3;
this.lineWidthMin = 1;
this.lineWidthMax = 60;
};
this.options = new f();
if(typeof options === "object"){
for(i in options){
this.options[i] = options[i];
}
}
};
vCode.prototype.update = function(){
for(var i=0; i<this.codeDoms.length; i++){
this.dom.removeChild(this.codeDoms[i]);
}
for(var i=0; i<this.lineDoms.length; i++){
this.dom.removeChild(this.lineDoms[i]);
}
this.createCode();
this.draw();
};
vCode.prototype.createCode = function(){
this.code = randstr(this.options.len);
};
vCode.prototype.verify = function(code){
return this.code === code;
};
vCode.prototype.draw = function(){
this.codeDoms = [];
for(var i=0; i<this.code.length; i++){
this.codeDoms.push(this.drawCode(this.code[i], i));
}
this.drawLines();
};
vCode.prototype.drawCode = function(code, index){
var dom = document.createElement("span");
dom.style.cssText = [
"font-size:" + randint(this.options.fontSizeMin, this.options.fontSizeMax) + "px",
"color:" + this.options.colors[randint(0, this.options.colors.length - 1)],
"position: absolute",
"left:" + randint(this.uW * index, this.uW * index + this.uW - 10) + "px",
"top:" + randint(0, this.h - 30) + "px",
"transform:rotate(" + randint(-30, 30) + "deg)",
"-ms-transform:rotate(" + randint(-30, 30) + "deg)",
"-moz-transform:rotate(" + randint(-30, 30) + "deg)",
"-webkit-transform:rotate(" + randint(-30, 30) + "deg)",
"-o-transform:rotate(" + randint(-30, 30) + "deg)",
"font-family:" + this.options.fonts[randint(0, this.options.fonts.length - 1)],
"font-weight:" + randint(400, 900)
].join(";");
dom.innerHTML = code;
this.dom.appendChild(dom);
return dom;
};
vCode.prototype.drawLines = function(){
this.lineDoms = [];
for(var i=0; i<this.options.lines; i++){
var dom = document.createElement("div");
dom.style.cssText = [
"position: absolute",
"opacity: " + randint(3, 8) / 10,
"width:" + randint(this.options.lineWidthMin, this.options.lineWidthMax) + "px",
"height:" + randint(this.options.lineHeightMin, this.options.lineHeightMax) + "px",
"background: " + this.options.lineColors[randint(0, this.options.lineColors.length - 1)],
"left:" + randint(0, this.w - 20) + "px",
"top:" + randint(0, this.h) + "px",
"transform:rotate(" + randint(-30, 30) + "deg)",
"-ms-transform:rotate(" + randint(-30, 30) + "deg)",
"-moz-transform:rotate(" + randint(-30, 30) + "deg)",
"-webkit-transform:rotate(" + randint(-30, 30) + "deg)",
"-o-transform:rotate(" + randint(-30, 30) + "deg)",
"font-family:" + this.options.fonts[randint(0, this.options.fonts.length - 1)],
"font-weight:" + randint(400, 900)
].join(";");
this.dom.appendChild(dom);
this.lineDoms.push(dom);
}
};
this.vCode = vCode;
}).call(this);
用法：
//container 为 验证码的DOM节点
var code = new vCode(container);
// 验证是否正确
// inputCode为用户输入的验证码
code.verify(inputCode); // return true or false
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