Form wont recognize script

Can anyone help?  I insert this script, in design studio on PO31; even if the text37 is empty the process still goes through and dont trigger the script to run.

function BUTTON_OnClick(id, row)
{
 if (id == "button8")  //When the shipped button is pressed
 {
  var compValue=lawForm.getFormValue("text37");
  if (compValue == "")
  {
   alert("Message");
   lawForm.positionInFieldById("text37");
   return false;
  }
 } 
 return true;
}

Thanks in advanced