JavaScript客户端登录验证实践

///登录

function check_form() {
  if (document.form1.user_name.value == "") {
    alert('请输入您的用户名...');
    document.form1.user_name.focus();
    return false;
  }  if (document.form1.pass_wd.value == "") {
    alert('请输入您的密码...');
    document.form1.pass_wd.focus();
    return false;
  }
  document.form1.passwd.value=document.form1.pass_wd.value;
  document.form1.Mname.value=document.form1.user_name.value;
  document.form1.Mpassword.value=document.form1.pass_wd.value;
  
  document.form1.USER_NAME.value=document.form1.user_name.value;
  document.form1.PASSWORD.value=document.form1.pass_wd.value;
  document.form1.rand.value=document.form1.Maddword.value;
  
  return true;
  }

///验证是否为空

  <script type="text/javascript">
function checkvalue()
{
if(document.upform.upfile.value=="" || document.upform.upfile.value==null){
alert("请选择发送文件！");