function extractNumber(obj, decimalPlaces, allowNegative)
{
	var temp = obj.value;
	
	// avoid changing things if already formatted correctly
	var reg0Str = '[0-9]*';
	if (decimalPlaces > 0) {
		reg0Str += '\\.?[0-9]{0,' + decimalPlaces + '}';
	} else if (decimalPlaces < 0) {
		reg0Str += '\\.?[0-9]*';
	}
	reg0Str = allowNegative ? '^-?' + reg0Str : '^' + reg0Str;
	reg0Str = reg0Str + '$';
	var reg0 = new RegExp(reg0Str);
	if (reg0.test(temp)) return true;

	// first replace all non numbers
	var reg1Str = '[^0-9' + (decimalPlaces != 0 ? '.' : '') + (allowNegative ? '-' : '') + ']';
	var reg1 = new RegExp(reg1Str, 'g');
	temp = temp.replace(reg1, '');

	if (allowNegative) {
		// replace extra negative
		var hasNegative = temp.length > 0 && temp.charAt(0) == '-';
		var reg2 = /-/g;
		temp = temp.replace(reg2, '');
		if (hasNegative) temp = '-' + temp;
	}
	
	if (decimalPlaces != 0) {
		var reg3 = /\./g;
		var reg3Array = reg3.exec(temp);
		if (reg3Array != null) {
			// keep only first occurrence of .
			//  and the number of places specified by decimalPlaces or the entire string if decimalPlaces < 0
			var reg3Right = temp.substring(reg3Array.index + reg3Array[0].length);
			reg3Right = reg3Right.replace(reg3, '');
			reg3Right = decimalPlaces > 0 ? reg3Right.substring(0, decimalPlaces) : reg3Right;
			temp = temp.substring(0,reg3Array.index) + '.' + reg3Right;
		}
	}
	
	obj.value = temp;
}
function blockNonNumbers(obj, e, allowDecimal, allowNegative)
{
	var key;
	var isCtrl = false;
	var keychar;
	var reg;
		
	if(window.event) {
		key = e.keyCode;
		isCtrl = window.event.ctrlKey
	}
	else if(e.which) {
		key = e.which;
		isCtrl = e.ctrlKey;
	}
	
	if (isNaN(key)) return true;
	
	keychar = String.fromCharCode(key);
	
	// check for backspace or delete, or if Ctrl was pressed
	if (key == 8 || isCtrl)
	{
		return true;
	}

	reg = /\d/;
	var isFirstN = allowNegative ? keychar == '-' && obj.value.indexOf('-') == -1 : false;
	var isFirstD = allowDecimal ? keychar == '.' && obj.value.indexOf('.') == -1 : false;
	
	return isFirstN || isFirstD || reg.test(keychar);
}

function doTotal(form) {

	/*var a = (form.h2s.value != '') ? eval(form.h2s.value) : 0; */
	var b = (form.n2.value != '') ? eval(form.n2.value) : 0;
	var c = (form.o2.value != '') ? eval(form.o2.value) : 0;
	var d = (form.co2.value != '') ? eval(form.co2.value) : 0;
	var e = (form.c.value != '') ? eval(form.c.value) : 0;
	var f = (form.c2.value != '') ? eval(form.c2.value) : 0;
	var g = (form.c3.value != '') ? eval(form.c3.value) : 0;
	var h = (form.ic4.value != '') ? eval(form.ic4.value) : 0;
	var i = (form.nc4.value != '') ? eval(form.nc4.value) : 0;
	var j = (form.ic5.value != '') ? eval(form.ic5.value) : 0;
	var k = (form.nc5.value != '') ? eval(form.nc5.value) : 0;
	var l = (form.c6.value != '') ? eval(form.c6.value) : 0;
	
	var temp;
	
	//temp = a + b + c + d + e + f + g + h + i + j + k + l;
	
	temp = b + c + d + e + f + g + h + i + j + k + l;
	
	temp = ((Math.round(temp * 100000000)) / 100000000);
	
	form.total.value = temp;
	
	//var t = a + b + c + d + e + f + g + h + i + j + k + l;
	
	//var t = b + c + d + e + f + g + h + i + j + k + l;
	
	

	if(temp != 100) {
	
		form.total.style.color = "red";
		document.getElementById('validate_error').style.visibility = "visible";
	
	}
	
	if(temp == 0){
	
		form.total.style.color = "black";
		document.getElementById('validate_error').style.visibility = "hidden";

	}
	
	if(temp == 100) {
	
		form.total.style.color = "black";
		document.getElementById('validate_error').style.visibility = "hidden";
	}
	
	if(temp == '') {
	
		form.total.style.color = "black";
		document.getElementById('validate_error').style.visibility = "hidden";
	}
}

function checkdate(input){

	var validformat=/^\d{4}\-\d{2}\-\d{2}$/ //Basic check for format validity
	
	/*if(input.value == NULL)
		returnval=true; */
	
	var returnval=false
	
	if (!validformat.test(input.value))
		alert("Invalid Date Format (yyyy-mm-dd). Please correct and submit again.")
		
	else { //Detailed check for valid date ranges
	
		var yearfield=input.value.split("-")[0]
		var monthfield=input.value.split("-")[1]
		var dayfield=input.value.split("-")[2]
		var dayobj = new Date(yearfield, monthfield-1, dayfield)
		
		/*if ((dayobj.getFullYear()!=yearfield)||(dayobj.getMonth()+1!=monthfield)||(dayobj.getDate()!=dayfield))
		
			alert("Invalid Day, Month, or Year range detected. Please correct and submit again.")
			
		else
		
			returnval=true */
	}
	
	if (returnval==false) input.select()
		return returnval
}