本文实例为大家分享了H5+css3+js搭建带验证码的登录页面，供大家参考，具体内容如下
login.html
<!DOCTYPE HTML>
<html>
<head>
<title>EasyBuy后台管理系统</title>
<meta charset="utf-8">
<style>
.main_bar{
width:1350px;
height:350px;
background-color:#6495ED;
margin-top:10%;
}
#login_form{
width:40%;
height:100%;
background-color:#112435;
margin:0 auto;
}
.title{
width:100%;
height:55px;
color:#ffffff;
border-bottom:1px solid #ffffff;
font-size:20pt;
font-family:"微软雅黑";
line-height:55px;
text-align:center;
}
#form_widget{
width:100%;
height:295px;
background-color:#808080;
}
.txt{
display:block;/*设置为独立块（换行）*/
width:70%;
margin:0 auto;
height:35px;
font-size:15pt;
border-radius:5px;/*设置圆角样式*/
border:0;
padding-left:8px;
}
#vcode{
height:35px;
width:40%;
font-size:15pt;
margin-left:15%;
border-radius:5px;
border:0;
padding-left:8px;
}
#code{
color:#ffffff;/*字体颜色白色*/
background-color:#000000;
font-size:20pt;
font-family:"华康娃娃体W5";
padding:5px 35px 10px 35px;
margin-left:5%;
cursor:pointer;
}
#search_pass_link{
width:70%;
text-align:right;
margin:0 auto;
padding:5px;
}
/*层级选择器*/
#search_pass_link a{
color:#000000;
text-decoration:none;
}
/*伪类*/
#search_pass_link a:hover{
color:#ff0000;
text-decoration:underline;
}
.btn{
width:70%;
margin-left:15%;
height:40px;
border:0;
font-size:14pt;
font-family;"微软雅黑";
background-color:#FC5628;
color:#ffffff;
cursor:pointer;/*设置指针鼠标的样式*/
border-radius:20px;/*设置圆角样式*/
border:0;
}
#copyright{
width:100%;
text-align:center;
padding-top:20px;
font-family:"微软雅黑";
color:#e0e0e0;
}
</style>
</head>
<body leftmargin="0" οnlοad="changeImg()">
<div class="main_bar">
<div id="login_form">
<div class="title">
EasyBuy系统登录
</div>
<form action="main.html" οnsubmit="return check()">
<div id="form_widget">
<br>
<input type="text" placeholder="请输入账号" id="box_name" class="txt" value="用户名" οnfοcus="this.value=''" οnblur="if(this.value=='')this.value='用户名'"/>
<br>
<input type="password" placeholder="请输入密码" id="box_pass" class="txt" value="password" οnfοcus="this.value=''" οnblur="if(this.value=='')this.value='password'"/>
<br>
<input type="text" id="vcode" placeholder="验证码" value="验证码" οnfοcus="this.value=''" οnblur="if(this.value=='')this.value='验证码'"/><span id="code" title="看不清，换一张"></span>
<div id="search_pass_link">
<a href="#" rel="external nofollow" >忘记密码？</a>
</div>
<input type="submit" value="登录" class="btn" οnmοuseοver="this.style.backgroundColor='#FF8D00'" οnmοuseοut="this.style.backgroundColor='#FC5628'">
<br>
<div id="copyright">
Power By WXH ©CopyRight 2016
</div>
</div>
</form>
</div>
</div>
</body>
<script type="text/javascript">
var code;//声明一个变量用于存储生成的验证码
document.getElementById("code").οnclick=changeImg;
function changeImg(){
//alert("换图片");
var arrays=new Array(
'1','2','3','4','5','6','7','8','9','0',
'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'
);
code='';//重新初始化验证码
//alert(arrays.length);
//随机从数组中获取四个元素组成验证码
for(var i=0;i<4;i++){
//随机获取一个数组的下标
var r=parseInt(Math.random()*arrays.length);
code+=arrays[r];
//alert(arrays[r]);
}
//alert(code);
document.getElementById('code').innerHTML=code;//将验证码写入指定区域
}
//效验验证码(表单被提交时触发)
function check(){
//获取用户输入的验证码
var input_code=document.getElementById('vcode').value;
//alert(input_code+"----"+code);
if(input_code.toLowerCase()==code.toLowerCase())
{
//验证码正确(表单提交)
return true;
}
alert("请输入正确的验证码!");
//验证码不正确,表单不允许提交
return false;
}
</script>
</html>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。