TE Comp Sem-II CN Prac 9 (Javascript)

function validateForm()
{
var x=document.forms["myForm"]["fname"].value
if (x==null || x=="")
  {
  alert("First name must be filled out");
  return false;
  }

}

<form name="myForm" action="demo_form.asp" onsubmit="return validateForm()" method="post">

First name: <input type="text" name="fname">

<input type="submit" value="Submit">

</form>