HTML最简单的MD5密码登录方法：

页面中：

<script src="https://cdn.bootcdn.net/ajax/libs/blueimp-md5/2.16.0/js/md5.min.js"></script>
<input placeholder="密码" style="width:70%;min-width: 100px" id="password" type="password" name="password" value="" class="input" />
<input type="submit" class="button" value="登　录" onclick="submitForm()"/>
<script>
  function submitForm() {
    var pass = $('#password').val();
    $('#password').val(md5(pass));
  }
</script>