<form name="frmtest" onsubmit="return checkInput()">
<input type="text" name="tt">
<input type="submit" name="b" value="submit">
</form><script language="javascript">
function checkInput()
{
if (document.frmtest.tt.value == "")
return false;
return true;
}
</script>
<input type="text" name="tt">
<input type="submit" name="b" value="submit">
</form><script language="javascript">
function checkInput()
{
if (document.frmtest.tt.value == "")
return false;
return true;
}
</script>
function document.onkeydown()
{
var obj = event.srcElement;
if (event.keyCode == 13)
{
if (obj.type.toLowerCase() == "text" && obj.form != null)
{
event.cancelBubble = true;
event.returnValue = false;
}
}}
</script>