<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script> function check() { //教研名字 var firstnamev = document.getElementById('firstname').value; if (firstnamev == '') { alert('名字不能为空'); return false; } else { for (var i = 0; i < firstnamev.length; i++) { var c = firstnamev[i]; if (c >= 0) { alert('名字不能包含数字'); return false; } } } //教研姓氏 var lastnamev = document.getElementById('lastname').value; if (lastnamev == '') { alert('姓氏不能为空'); return false; } else { for (var j = 0; j < lastnamev.length; j++) { var cl = lastnamev[j]; if (cl >= 0) { alert('姓氏不能包含数字'); return false; } } } //校验邮箱 var emailv = document.getElementById('email').value; if (emailv == '') { alert('邮箱不能为空！'); return false; } else { var index1 = emailv.indexOf('@');//字符串中包含“@” var index2 = emailv.indexOf('.');//字符串中包含“.” if (index1 == -1 || index2 == -1) {//@,.不存在 alert('邮箱地址不合法！'); return false; } else if (index1 >= index2) {//@在.的后面,索引大于. alert('邮箱地址不合法！'); return false; } } //校验密码 var p = document.getElementById('password').value; if (p == '') { alert('密码不能为空!'); return false } else if (p.length <= 3) { alert('密码长度小于6!'); return false; } var chekpsdv = document.getElementById('check_password').value; if (chekpsdv == '') { alert('请再次输入密码'); return false; } else if (chekpsdv != p) { alert('两次输入密码不一致'); return false; } } </script> </head> <body> <form action="do.html" onsubmit="return check();"> 名字：<input type="text" id="firstname"><br> 姓氏：<input type="text" id="lastname"><br> 邮箱：<input type="text" name="" id="email"><br> 密码：<input type="txt" name="" id="password"><br> 再次输入密码：<input type="txt" name="" id="check_password"><br> <input type="submit" value="提交"> </form> </body> </html>