Detailed explanation on the submission usage of form form submit and button in html-HTML Tutorial-php.cn

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Detailed explanation on the submission usage of form form submit and button in html

黄舟

May 25, 2018 am 11:27 AM

form html submit

1. When the entered username and password are empty, judgment is required. At this time, verification of username and password is used. This needs to be written on the front-end page of jsp; there are two methods, one is to submit using submit. One is to submit using button.
Method one:
Insert a js method in the head of the jsp front-end page:

function checkUser(){
   var result = document.getElementById("userid").value;
   var password = document.getElementById("userpassid").value;
   if(result == ""  ){
     alert("用户名不能为空");
     return false;
   }
   if(password == ""  ){
    alert("密码不能为空");
     return false;
   }else{
   return true;
   }
}

Copy after login

Write it like this in the form:

<form id="formid"  name= "myform" method = &#39;post&#39;  action = &#39;user_login_submit.action&#39;
onsubmit = "return checkUser();
" >
            <table width="100%" border="0">
              <tr>
                <td width="60" height="40" align="right">用户名 </td>
                <td><input type="text" value="" class="text2" name = "username" id = "userid"/></td>
              </tr>
              <tr>
                <td width="60" height="40" align="right">密  码 </td>
                <td><input type="password" value="" class="text2" name = "userpass" id = "userpassid"/></td>
              </tr>
              <tr>
                <td width="60" height="40" align="right"> </td>
                <td><p class="c4">
                    <input type="submit" value="" class="btn2"  />

Copy after login

Method two:

function checkUser(){
   var result = document.getElementById("userid").value;
   var password = document.getElementById("passid").value;
   if(result == ""  ){
     alert("用户名不能为空");
     return false;
   }
   if(password == ""  ){
    alert("密码不能为空");
     return false;
   }
  document.getElementById("formid").submit();
}

Copy after login

For the form, you need to write the id

<form id="formid" method = &#39;post&#39;  action = &#39;user_login_submit.action&#39;  >

Copy after login

The button button is written as follows:

<input type="button" value="" class="btn2" onclick = "checkUser();" />

Copy after login

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