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。

14129549352498

Code代码:

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/**
* Created by Lee on 2014/9/16.
*/
(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:

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//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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