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