JavaScript 正则表达式实现输入框验证功能详解

<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="utf-8">
		<title>密码框验证信息</title>
		<style type="text/css">
			* {
				padding: 0;
				margin: 0;
			}

			div {
				width: 800px;
				height: 30px;
				margin: 20px auto;
			}

			.info {
				/* background-color: #41b916; */
				width: 60px;
				height: 100%;
				text-align: right;
				display: inline-block;
			}

			.ipt {
				width: 200px;
				height: 100%;
				line-height: 30px;
				padding: 5px;
				box-sizing: border-box;
			}

			.message {
				display: inline-block;
				color: #999;
				background: url(img/提示.png) no-repeat left center;
				font-size: 12px;
				padding-left: 24px;
				height: 100%;
				line-height: 30px;
				text-align: center;
			}

			.wrong {
				color: #ee2c13;
				background-image: url(img/关闭圆.png);
			}

			.right {
				color: #41b916;
				background-image: url(img/选中圆.png);
			}
		</style>
		<script type="text/javascript">
			window.onload = function() {


				//获取元素
				var realname = document.querySelector('#realname');
				var realnamemsg = document.querySelector('#realnamemsg');

				var psd = document.querySelector('#psd')
				var psdmsg = document.querySelector('#psdmsg')

				var email = document.querySelector('#email')
				var emailmsg = document.querySelector('#emailmsg')

				var phone = document.querySelector('#phone')
				var phonemsg = document.querySelector('#phonemsg')

				//验证用户名
				realname.onblur = function() {

					var value = realname.value;
					var reg = /^[a-zA-Z][a-zA-Z0-9_]{4,15}$/; //帐号是否合法(字母开头，允许5-16字节，允许字母数字下划线)
					var flag = reg.test(value);
					if (!flag) {
						realnamemsg.className = "message wrong";
						realnamemsg.innerHTML = "请输入正确的用户名"
					} else {
						realnamemsg.className = "message right";
						realnamemsg.innerHTML = "用户名输入正确"
					}
				}

				//验证密码
				psd.onblur = function() {

					var value = psd.value;
					var reg = /^[a-zA-Z]\w{5,17}$/; //密码(以字母开头，长度在6~18之间，只能包含字母、数字和下划线)
					var flag = reg.test(value);
					if (!flag) {
						psdmsg.className = "message wrong";
						psdmsg.innerHTML = "请输入正确的密码"
					} else {
						psdmsg.className = "message right";
						psdmsg.innerHTML = "密码正确"
					}
				}

				//验证邮箱
				email.onblur = function() {

					var value = email.value;
					var reg = /^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/; //验证邮箱
					var flag = reg.test(value);
					if (!flag) {
						emailmsg.className = "message wrong";
						emailmsg.innerHTML = "请输入正确的邮箱号"
					} else {
						emailmsg.className = "message right";
						emailmsg.innerHTML = "邮箱正确"
					}
				}

				//验证手机号
				phone.onblur = function() {

					var value = phone.value;
					var reg = /^(13[0-9]|14[01456879]|15[0-35-9]|16[2567]|17[0-8]|18[0-9]|19[0-35-9])\d{8}$/; //验证手机号码
					var flag = reg.test(value);
					if (!flag) {
						phonemsg.className = "message wrong";
						phonemsg.innerHTML = "请输入正确的手机号码"
					} else {
						phonemsg.className = "message right";
						phonemsg.innerHTML = "号码正确"
					}
				}
			}
		</script>

	</head>
	<body>

		<div>
			<p class="info">用户名</p>
			<input type="text" class="ipt" id="realname">
			<p class="message" id="realnamemsg">请输入6~10位用户名，以字母开头，允许字母数字下划线</p>
		</div>
		<div>
			<p class="info">密码</p>
			<input type="password" class="ipt" id="psd">
			<p class="message" id="psdmsg">密码以字母开头，长度在6~18之间，只能包含字母、数字和下划线</p>
		</div>
		<div>
			<p class="info">邮箱</p>
			<input type="email" class="ipt" id="email">
			<p class="message" id="emailmsg">请输入正确的邮箱账号</p>
		</div>
		<div>
			<p class="info">手机号</p>
			<input type="text" class="ipt" id="phone">
			<p class="message" id="phonemsg">请输入正确的手机号码</p>
		</div>

	</body>
</html>

var res = RegExp(“[0-9]{2}”);
var regex = res.exec(1234567);//[“12”, index: 0, input: “1234567”]

var res = new RegExp(“[0-9]{2}”);
var result = res.test(1234567);