function trim(str) {
	return str.replace(/^\s+|\s+$/g, '')
};

function isNumeric(str) {
	var validChars = "0123456789.";
	var isNumber=true;
	var cchar;
 
	for (i=0; i<str.length; i++) { 
		cchar = str.charAt(i); 
		if (validChars.indexOf(cchar) == -1) {
         isNumber = false;
			break;
		}
	}

	return(isNumber);
}
   
function isEmail(s) {
	var i = 1;
	var sLength = s.length;

	// look for @
	while ((i < sLength) && (s.charAt(i) != "@")) { 
		i++; 
	}

	if ((i >= sLength) || (s.charAt(i) != "@")) {
		return false;
	} else {
		i += 2;
	}

	// look for .
	while ((i < sLength) && (s.charAt(i) != ".")) { 
		i++; 
	}

	// there must be at least one character after the .
	if ((i >= sLength - 1) || (s.charAt(i) != ".")) {
		return false;
	} else {
		return true;
	}
}

function hasValue(val) {
    if (val == null) {
        return(false);
    }

    var s = trim(val);

    if (s == "") {
        return(false);
    }

    return(true);

}

function isBlank(val) {
	return(!hasValue(val));
}

function randomInt(upperBound) {
	return( Math.round((Math.random()*upperBound) + 0.5) );
}

function hideElement(elementId) {
	var elm = document.getElementById(elementId);

	if (null === elm) {
		alert("Fatal error: Could not locate element with id '" + elementId + "'");
	} else {
		elm.style.display = "none";
	}
}

function showElement(elementId) {
	var elm = document.getElementById(elementId);

	if (null === elm) {
		alert("Fatal error: Could not locate element with id '" + elementId + "'");
	} else {
		elm.style.display = "block";
	}
}

function updatePrice(id) {
	//alert("Would update prices for " + id);
	var menu = document.getElementById("menu_" + id);
	var im = document.getElementById("prices_" + id);

	if (menu == null) {
		alert("Fatal error updating ");
		return;
	}

	var idx = menu.selectedIndex;
	var data = menu.options[idx].value;
	//var imgUrl = "/pricegroupgraph.php?id=" + id + "&weeks=" + data;
	var imageName = id + "_" + data + ".png";
	var imgUrl = "/pricegraphs/" + imageName;
	im.src = imgUrl;	
}