js實現驗證碼干擾（動態）
阿新 • • 發佈：2021-02-26
本文例項為大家分享了js實現驗證碼動態干擾的具體程式碼，供大家參考，具體內容如下
效果一
效果二
程式碼一
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>js簡單驗證碼使用</title>
<style>
.code
{
font-family:Arial;
font-style:italic;
color:blue;
font-size:30px;
border:0;
padding:2px 3px;
letter-spacing:3px;
font-weight:bolder;
float:left;
cursor:pointer;
width:150px;
height:50px;
line-height:60px;
text-align:center;
vertical-align:middle;
background-color:#D8B7E3;
}
span {
text-decoration:none;
font-size:12px;
color:#288bc4;
padding-left:10px;
}
span:hover {
text-decoration:underline;
cursor:pointer;
}
</style>
<script>
//頁面載入時，生成隨機驗證碼
window.onload=function(){
createCode(4);
}
//生成驗證碼的方法
function createCode(length) {
var code = "";
var codeLength = parseInt(length); //驗證碼的長度
var checkCode = document.getElementById("checkCode");
所有候選組成驗證碼的字元，當然也可以用中文的
var codeChars = 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','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');
//迴圈組成驗證碼的字串
for (var i = 0; i < codeLength; i++)
{
//獲取隨機驗證碼下標
var charNum = Math.floor(Math.random() * 62);
//組合成指定字元驗證碼
code += codeChars[charNum];
}
if (checkCode)
{
//為驗證碼區域新增樣式名
checkCode.className = "code";
//將生成驗證碼賦值到顯示區
checkCode.innerHTML = code;
}
}
//檢查驗證碼是否正確
function validateCode()
{
//獲取顯示區生成的驗證碼
var checkCode = document.getElementById("checkCode").innerHTML;
//獲取輸入的驗證碼
var inputCode = document.getElementById("inputCode").value;
console.log(checkCode);
console.log(inputCode);
if (inputCode.length <= 0)
{
alert("請輸入驗證碼！");
}
else if (inputCode.toUpperCase() != checkCode.toUpperCase())
{
alert("驗證碼輸入有誤！");
createCode(4);
}
else
{
alert("驗證碼正確！");
}
}
</script>
</head>
<body>
<table border="0" cellspacing="5" cellpadding="5" >
<tr>
<td> <div id="checkCode" class="code" onclick="createCode(4)" ></div></td>
<td> <span onclick="createCode(4)">看不清換一張</span></td>
</tr>
<tr>
<td>驗證碼：</td>
<td><input type="text" id="inputCode" style="float:left;" /></td>
</tr>
<tr>
<td></td>
<td><input type="button" onclick="validateCode()" value="確定" /></td>
</tr>
</table>
</div>
</body>
</html>程式碼二
<!DOCTYPE html>
<html>
<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>canvas驗證碼</title>
</head>
<body>
<canvas width="200" height="60" id="check" style="border:1px solid #000;">您的瀏覽器不支援canvas標籤！</canvas>
<script>
var ctx = document.getElementById("check").getContext("2d");
var ctxW = document.getElementById("check").clientWidth;
var ctxH = document.getElementById("check").clientHeight;
/**
* 產生一個隨機數 可設定隨機數區間
* @param {[Number]} min [隨機數區間下限]
* @param {[Number]} max [隨機數區間上限]
* @return {[Number]} [返回一個在此區間的隨機數]
*/
function ranNum(min,max) {
return Math.random() * (max - min) + min;
}
/**
* 返回一個隨機顏色 可設定顏色區間
* @param {[Number]} min [顏色下限]
* @param {[Number]} max [顏色上限]
* @return {[String]} [隨機顏色]
*/
function ranColor(min,max) {
var r = ranNum(min,max);
var g = ranNum(min,max);
var b = ranNum(min,max);
// return "rgb(" + r + "," + g + "," + b + ")";
return `rgb(${r},${g},${b})`;
}
/**
* 隨機字串陣列
* @return {[Array]} [隨機陣列]
*/
function ranStr() {
var str = "QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm0123456789";
return str.split("").sort(function () {
return Math.random() - 0.5
});
}
/**
* 繪製文字字串
* @param {[String]} canvasId [canvas的id]
* @param {[Number]} canvasW [canvas的width]
* @param {[Number]} canvasH [canvas的height]
* @param {[Number]} num [繪製驗證碼的字數]
* @param {[Number]} fsMin [字型大小下限]
* @param {[Number]} fsMax [字型大小上限]
* @param {[Number]} frMin [字型旋轉偏移下限]
* @param {[Number]} frMax [字型旋轉偏移上限]
* @param {[Number]} min [顏色下限]
* @param {[Number]} max [顏色上限]
* @return {[String]} [隨機字串]
*/
function drawText(canvasId,canvasW,canvasH,num,fsMin,fsMax,frMin,frMax,min,max) {
var str = "";
for (var i = 0; i < num; i++) {
var char = ranStr()[Math.floor(0,ranStr().length)];
var fs = ranNum(fsMin,fsMax);
canvasId.font = fs + "px Verdana";
can
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支援我們。