老师请问一下怎么停止加载页面呢

来源：3-9 编程练习

慕斯卡8252506

2019-07-20 14:29:19

<!DOCTYPE html>
<html>
   <head>
       <meta charset="utf-8" />
       <title>练习</title>
       <style type="text/css">form {
   width: 300px;
   background: pink;
   text-align: center;
   padding: 30px 0;
   margin: 100px auto;
}</style>
   </head>
   <body>
   <form id="form">
        <p><input type="text" name="name" id="username" placeholder="请输入账户名"></p>
        <span></span>
        <p><input type="text" name="chinaName" id="chinaName" placeholder="请输入中文名"></p>
        <span></span>
        <p><input type="email" name="eamil" id="email" placeholder="请输入邮箱"></p>
        <span></span>
        <p><input type="submit" value="注册" id="submit"></p>
    </form>
    <script type="text/javascript">var spans = document.getElementsByTagName("span");
var username = document.getElementById("username");
var chinaName = document.getElementById("chinaName");
var email = document.getElementById("email");
var submit = document.getElementById("submit");
var input1 = false;
var input2 = false;
var input3 = false;

username.onfocus = function() {
   spans[0].innerHTML = "用户名不能为空";
}
username.onblur = function() {
   var patt = /\w{6,18}/
   if(!patt.exec(this.value)) {
       spans[0].innerHTML = "6-18位字母、数字或“_”,字母开头"
   } else {
       spans[0].innerHTML = "";
       input1 = true;
   }
}
chinaName.onfocus = function() {
   spans[1].innerHTML = "真实名字不能为空";
}
chinaName.onblur = function() {
   var patt = /[\u4e00-\u9fa5]{2,5}/
   if(!patt.exec(this.value)) {
       spans[1].innerHTML = "请输入2-5为中文名字"
   } else {
       spans[1].innerHTML = "";
       input2 = true;
   }
}
email.onfocus = function() {
   spans[2].innerHTML = "邮箱不能为空";
}
email.onblur = function() {
   var patt = /\w+@\w+\.[a-zA-z_]/
   if(!patt.exec(this.value)) {
       spans[2].innerHTML = "格式有误，请重新输入"
   } else {
       spans[2].innerHTML = "";
       input3 = true;
   }
}

//点击注册时，验证用户填写的全部信息
submit.onclick = function() {
   if(input1 == false || input2 == false || input3 == false) {
       alert("请按要求填写信息");
   } else {
       alert("注册成功");
   }
}</script>
   </body>
</html>