function toggle_visibility(id) { 
var e = document.getElementById(id); 
if(e.style.display == 'none') 
  e.style.display = 'block'; 
else 
  e.style.display = 'none'; 
}
//myField accepts an object reference, myValue accepts the text string to add 
function insertAtCursor(myField, myValue) { 
  //IE support 
  if (document.selection) { 
    myField.focus(); 
    //in effect we are creating a text range with zero 
    //length at the cursor location and replacing it 
    //with myValue 
    sel = document.selection.createRange(); 
    sel.text = myValue;
    } 

  //Mozilla/Firefox/Netscape 7+ support 
  else if (myField.selectionStart || myField.selectionStart == '0') { 
      //Here we get the start and end points of the 
      //selection. Then we create substrings up to the 
      //start of the selection and from the end point 
      //of the selection to the end of the field value. 
      //Then we concatenate the first substring, myValue, 
      //and the second substring to get the new value. 
      var startPos = myField.selectionStart; 
      var endPos = myField.selectionEnd; 
      myField.value = myField.value.substring(0, startPos)+ myValue+ myField.value.substring(endPos, myField.value.length);
      myField.focus();
      myField.selectionStart = startPos + myValue.length;
      myField.selectionEnd = startPos + myValue.length; 
      }
   else { 
      myField.value += myValue; 
      myField.focus(); 
      } 
}