1 JS实现验证码倒计时效果
效果如下：
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<script type="text/javascript" src="../static/js/jquery-1.9.1.min.js"></script>
<script type="text/javascript">
$(function () {
var wait=30;
function time(o){
if (wait==0) {
o.removeAttribute("disabled");
o.innerHTML="输入验证码";
o.style.backgroundColor="#fe9900";
wait=30;
}else{
o.setAttribute("disabled", true);
o.innerHTML=wait+"秒后重新获取";
o.style.backgroundColor="#8f8b8b";
wait--;
setTimeout(function(){
time(o)
},1000)
}
}
$(".getCode").click(function(){
time(this);
});
})
</script>
</head>
<body>
<button class="getCode" style="width: 120px;height: 50px;background: #FE9900;color: white;border: none">获取验证码</button>
</body>
</html>
2 JS生成验证码
效果如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JS生成验证码</title>
<style type="text/css">
.code {
background-image: url(code.jpg);
font-family: Arial;
font-style: italic;
color: Red;
border: 0;
padding: 2px 3px;
letter-spacing: 3px;
font-weight: bolder;
}
.unchanged {
border: 0;
}
</style>
<script language="javascript" type="text/javascript">
var code; //在全局 定义验证码
function createCode() {
code = "";
var codeLength = 4;//验证码的长度
var checkCode = document.getElementById("checkCode");
var selectChar = 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');//所有候选组成验证码的字符，当然也可以用中文的
for (var i = 0; i < codeLength; i++) {
var charIndex = Math.floor(Math.random() * 36);
code += selectChar[charIndex];
}
//alert(code);
if (checkCode) {
checkCode.className = "code";
checkCode.value = code;
}
}
function validate() {
var inputCode = document.getElementById("input1").value;
if (inputCode.length <= 0) {
alert("请输入验证码！");
} else if (inputCode != code) {
alert("验证码输入错误！");
createCode();//刷新验证码
} else {
alert("^-^ OK");
}
}
</script>
</head>
<body onload="createCode()">
<form action="#">
<input type="text" id="input1" /> <input type="text" onclick="createCode()" readonly="readonly" id="checkCode" class="unchanged" style="width: 80px" /><br />
<input id="Button1" onclick="validate();" type="button" value="确定" />
</form>
</body>
</html>
3 js 实现 图片刷新 验证码 看不清 换一张
【需求】
html+js实现html中一个图片刷新但是整个页面不刷新，或者是验证码刷新。
不使用jsp，不使用ajax，不使用js框架。
【原理】
当一个<img>的src改变时，页面会自动刷新这个<img>
【实现代码】
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>test</title>
<script type="text/javascript">
function reImg(){
var img = document.getElementById("Img");
img.src = "Img?rnd=" + Math.random();
}
</script>
</head>
<body>
<center>
<img id="Img" src="Img" alt="验证码" />
<a href="#" onclick="reImg();">看不清，换一张</a>
</center>
</body>
</html>