js实现注册表单验证
验证用户名必须为：要求6-20位，只能有大小写字母和数字，并且大小写字母和数字都要有
var name_re=/[0-9a-zA-Z]{3,8}/;
var pwd_re=/^\S{6,20}$/;
<!DOCTYPE html>
<html>
<head><meta charset="utf-8" /><title>js实现注册表单验证</title>
</head>
<body>
<form id="test-register" action="#" onsubmit="return checkRegisterForm()"><p id="test-error" style="color:red"></p><p>用户名: <input type="text" id="username" name="username"></p><p>密码: <input type="password" id="password" name="password"></p><p>确认密码: <input type="password" id="password2"></p><p><button type="submit">提交</button> <button type="reset">重置</button></p>
</form>
<script>// 用户名必须是3-8位英文字母或数字；// 口令必须是6-20位；// 两次输入口令必须一致function checkRegisterForm(){var username = document.getElementById("username");var password = document.getElementById("password");var password2 = document.getElementById("password2");var testerror = document.getElementById("test-error");var name_re=/^\S[0-9a-zA-Z]{3,8}/;var pwd_re=/^\S{6,20}$/;if(name_re.test(username.value)&&pwd_re.test(password.value)&&password.value===password2.value){alert("提交成功！");}if(!name_re.test(username.value)){alert("用户名必须是3-10位英文字母或数字");}if(!pwd_re.test(password.value)){alert("密码必须是6-20位");console.log("password="+password.value+"password2="+password2.value);}else{alert("密码符合 要求")}if(password.value!==password2.value){alert("密码输入不一致");}}
</script>
</body>
</html>
