function validate() {
    var returnval=true;
    var fromYearNum=parseInt(document.forms['main'].fromYear.value);
    if (fromYearNum + "" != "NaN") {
	    document.forms['main'].fromYear.value = fromYearNum;
	}

    var toYearNum=parseInt(document.forms['main'].toYear.value);
    if (toYearNum + "" != "NaN") {
	    document.forms['main'].toYear.value = toYearNum;
	}

    var surname=parseInt(document.forms['main'].surname.value);

   	if (isNaN(toYearNum)){
		document.forms['main'].toYear.value = document.forms['main'].fromYear.value;
		toYearNum=parseInt(document.forms['main'].toYear.value);
	} else {
		if (isNaN(fromYearNum)){
			document.forms['main'].fromYear.value = document.forms['main'].toYear.value;
			fromYearNum=parseInt(document.forms['main'].fromYear.value);
		}
	}
	
	var fromYearMin = 1761;
	if (document.forms['main'].searchType.value == 'M') {
		fromYearMin = 1818;
	} else if (document.forms['main'].searchType.value == 'D') {
		fromYearMin = 1796;
	}

    if (isNaN(fromYearNum) || fromYearNum < fromYearMin  || fromYearNum > 1994)    {
      document.forms['main'].fromYear.focus();
      alert("Please enter a valid year between " + fromYearMin + " and 1994");
      returnval = false;
    }    else    {
    	if (isNaN(toYearNum) || toYearNum < fromYearMin  || toYearNum > 1994)
      	{
        	document.forms['main'].toYear.focus();
        	alert("Please enter a valid year between " + fromYearMin + " and 1994");
        	returnval = false;
      	}
    }
    
    strName = document.forms['main'].surname.value;
    strCount = 0;
    for (i=0; i<strName.length; i++) {
	    if (strName.charAt(i) >= "A" && strName.charAt(i) <= "Z" ||
		    strName.charAt(i) >= "a" && strName.charAt(i) <= "z" )  {
	        strCount++;
	    }
	}

	if (strCount < 1) {
       	alert("Please enter a surname");
       	if (returnval == true) {
  	       	document.forms['main'].surname.focus();
	       	returnval = false;    
	    }
	}
	
    if (returnval == true)    {
    	document.forms['main'].submit();
    }
}

function resetForm(){
	document.forms['main'].reset();
}