JS带提示登录表单验证代码javascript
演示效果：
实现代码：
<!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带提示登录表单验证代码</title>
<style>
*{
margin:0;
padding:0;
font-family:"微软雅黑";
font-size:12px;
}
.box{
width:390px;
height:320px;
border:solid 1px #ddd;
background:#FFF;
position:absolute;
left:50%;
top:42%;
margin-left:-195px;
margin-top:-160px;
}
.box h2{
font-weight:normal;
color:#666;
font-size:16px;
line-height:46px;
height:46px;
overflow:hidden;
text-align:center;
border-bottom:solid 1px #ddd;
background:#f7f7f7;
}
.input_box{
width:350px;
padding-bottom:15px;
margin:0 auto;
overflow:hidden;
}
.input_box input{
float:left;
width:348px;
height:40px;
font-size:14px;
border:solid 1px #ddd;
text-indent:10px;
outline:none;
line-height:40px;
}
.input_box button{
width:350px;
height:48px;
background:#3f89ec;
border:none;
border-radius:2px;
outline:none;
cursor:pointer;
font-size:16px;
color:#FFF;
}
#error_box{
height:40px;
width:350px;
margin:0 auto;
line-height:40px;
color:#fc4343;
}
</style>
<script>
//长度必须在6~20位之间
//开头不能为数字
//只能包含小写字母和数字
//数字：48~57
//小写字母：97~122
//innerHTML
function fnLogin(){
var oUname = document.getElementById("uname");
var oUpass = document.getElementById("upass");
var oError = document.getElementById("error_box");
var isNotError = true;
if(oUname.value.length > 20 || oUname.value.length < 6){
oError.innerHTML = "用户名长度必须在6~20位之间";
isNotError = false;
return;
}else if(oUname.value.charCodeAt(0) >= 48 && oUname.value.charCodeAt(0) <= 57){
oError.innerHTML = "用户名开头不能为数字";
isNotError = false;
return;
}else{
for(var i=0; i<oUname.value.length; i++){
if((oUname.value.charCodeAt(i) > 122 || oUname.value.charCodeAt(i) < 97) && (oUname.value.charCodeAt(i) > 57 || oUname.value.charCodeAt(i) < 48)){
oError.innerHTML = "用户名只能包含小写字母和数字";
isNotError = false;
return;
}
}
}
if(oUpass.value.length > 20 || oUpass.value.length < 6){
oError.innerHTML = "密码长度必须在6~20位之间";
isNotError = false;
return;
}
oError.innerHTML = "登录成功";
}
</script>
</head>
<body>
<div class="box">
<h2>登录</h2>
<div id="error_box"></div>
<div class="input_box">
<input type="text" placeholder="请输入账户名" id="uname"/>
</div>
<div class="input_box">
<input type="password" placeholder="请输入密码" id="upass"/>
</div>
<div class="input_box">
<button onclick="fnLogin()">登录</button>
</div>
</div>
</body>
</html>
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