//form 
 
 
 
 

  
  //ajax提交表单 不需要依靠form标签。
 
 
 
 

  
  //我出现的问题是，在有<form action="/login" method="post">....</form>的时候，
 
 
 
 

  
  //ajax error处理函数，会自动跳转到一个页面，页面中显示返回的结果 例如{msg:'error'}
 
 
 
 
 
  
  16 
  
  <
  
  div 
  
  class
  
  =
  
  "login"
  
  >
 
 
 
 
 
  
  17     
  
  <
  
  p
  
  >
 
 
 
 
 
  
  18         
  
  <
  
  label 
  
  for
  
  =
  
  "login"
  
  >
  
  用户名
  
  :<
  
  /label>
 
 
 
 
 
  
  19         
  
  <
  
  input 
  
  type
  
  =
  
  "text" 
  
  name
  
  =
  
  "userName" 
  
  id
  
  =
  
  "userName" 
  
  placeholder
  
  =
  
  '' 
  
  value
  
  =
  
  "example"
  
  >
 
 
 
 
 
  
  20     
  
  <
  
  /p>
 
 
 
 
 
  
  21 
 
 
 
 
 
  
  22     
  
  <
  
  p
  
  >
 
 
 
 
 
  
  23         
  
  <
  
  label 
  
  for
  
  =
  
  "password"
  
  >
  
  密码
  
  :<
  
  /label>
 
 
 
 
 
  
  24         
  
  <
  
  input 
  
  type
  
  =
  
  "password" 
  
  name
  
  =
  
  "password" 
  
  id
  
  =
  
  "password" 
  
  placeholder
  
  =
  
  "example"
  
  >
 
 
 
 
 
  
  25     
  
  <
  
  /p>
 
 
 
 
 
  
  26 
 
 
 
 
 
  
  27     
  
  <
  
  p 
  
  class
  
  =
  
  "login-submit"
  
  >
 
 
 
 
 
  
  28         
  
  <
  
  button 
  
  class
  
  =
  
  "login-button"
  
  >
  
  Login
  
  <
  
  /button>
 
 
 
 
 
  
  29     
  
  <
  
  /p>
 
 
 
 
 
  
  30     
  
  <
  
  p 
  
  class
  
  =
  
  "forgot-password"
  
  >
  
  请输入用户名和密码
  
  <
  
  /p>
 
 
 
 
 
  
  31     
  
  <!--
  
  p 
  
  class
  
  =
  
  "forgot-password"
  
  ><
  
  a 
  
  href
  
  =
  
  "index.html"
  
  >
  
  Forgot 
  
  your 
  
  password
  
  ?<
  
  /a></p-->
 
 
 
 
 
  
  32 
  
  <
  
  /div>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
  //ajax
 
 
 
 
 
  
  34 
  
  <
  
  script
  
  >
 
 
 
 
 
  
  35     
  
  $
  
  (
  
  document
  
  ).
  
  ready
  
  (
  
  function
  
  (){
 
 
 
 
 
  
  36         
  
  $
  
  (
  
  '.login-button'
  
  ).
  
  on
  
  (
  
  'click'
  
  ,
  
  function
  
  (){
 
 
 
 
 
  
  37             
  
  var 
  
  userName 
  
  = 
  
  $
  
  (
  
  '#userName'
  
  ).
  
  val
  
  ();
 
 
 
 
 
  
  38             
  
  var 
  
  password 
  
  = 
  
  $
  
  (
  
  '#password'
  
  ).
  
  val
  
  ();
 
 
 
 
 
  
  39             
  
  console
  
  .
  
  log
  
  (
  
  userName
  
  ,
  
  password
  
  );
 
 
 
 
 
  
  40             
  
  if
  
  (
  
  !
  
  userName
  
  .
  
  length
  
  ){
 
 
 
 @H_403_451@ 
  
  41                 
  
  alert
  
  (
  
  '请输入用户名！'
  
  );