			<!--
			
				function IsNumeric(strString)
				//  check for valid numeric strings	
				{
					var strValidChars = "0123456789-Xx";
					var strChar;
					var blnResult = true;	

					if (strString.length == 0) return false;

					//  test strString consists of valid characters listed above
					for (i = 0; i < strString.length && blnResult == true; i++)
						{
						strChar = strString.charAt(i);
						if (strValidChars.indexOf(strChar) == -1)
							{
								blnResult = false;
							}
						}
					return blnResult;
				}
	
				function validateThenSubmit() {
					//if form is empty then display error
					if(document.getElementById('largeForm').search_isbn.value=="" && document.getElementById('largeForm').search_title.value=="" && document.getElementById('largeForm').search_author.value=="" && document.getElementById('largeForm').search_keyword.value=="" ) {
						alert("You did not include any search criteria.\nPlease try again.");
						return false;
					}
					//check that the ISBN field is numeric only
					else if(!IsNumeric(document.getElementById('largeForm').search_isbn.value) && document.getElementById('largeForm').search_isbn.value!="") {
						alert("The ISBN search criteria must be numeric.");
						return false;
					}
					else {
						document.getElementById('largeForm').search_isbn.value = stringFilter(document.getElementById('largeForm').search_isbn.value);
						document.getElementById('largeForm').submit();
					}
				}
				
				function submitenter(myfield,e)
				{
				var keycode;
				if (window.event) keycode = window.event.keyCode;
				else if (e) keycode = e.which;
				else return true;

				if (keycode == 13)
				   {
				   validateThenSubmit();
				   return false;
				   }
				else
				   return true;
				}
				
				//Strip out dashes from ISBN value
				function stringFilter(inputValue) {
					s = inputValue;
					filteredValues = "-";     // Characters stripped out
					var i;
					var returnString = "";
					for (i = 0; i < s.length; i++) {  // Search through string and append to unfiltered values to returnString.
					var c = s.charAt(i);
					if (filteredValues.indexOf(c) == -1) returnString += c;
					}
					return returnString;
				}
//-->