JavaScript中函数参数的传递问题

JavaScript中函数参数的传递问题
    <Script Language = "JavaScript">
     function mycheck(type){
       document.myform.type.value=type;
      
          if(document.myform.username.value=="") {
             alert("请输入用户名!");
             return;
          }
         
          if(document.myform.password.value=="") {
             alert("密码不能为空!");
             return;
          }
                   
          else if(document.myform.password.value!=document.myform.password2.value) {
            alert("两次输入的密码不一致，请重新输入!");
            return;
          }
         
          document.myform.submit();
     }
    </Script>