var TOTAL_CHARS = 400;	// max number of characters permitted
var COUNT_BREAK = 25;	// divisor for determining which interval the count is in.


// Calculate number of characters in text area
function calculateCharsLeft (text) {
	var val = text.length;
	var charsLeft = TOTAL_CHARS - parseInt(val);
	return parseInt(charsLeft);
}


// Get character count of user entered comment.
// Display message regarding how many characters are left.
// Hard-coded values from form elements are used.
function countDown () {
	var comment = document.getElementById("comment");
	var chars = calculateCharsLeft(comment.value);
	
	var details = document.getElementById("formDetails");
	var notes = details.innerHTML;
	var pattern = /\[([^\]]*)\]/g;	 // everything between square brackets []
	var origNote = notes.replace(pattern,"");
	
	//generate message dpending on how many caharacters are left
	if (TOTAL_CHARS == chars || (chars < COUNT_BREAK && chars >= 0)) { var newText = ' [' + String(chars) + ' characters left]';}
	else if (chars >= 0) {
		var newCount = (chars - (chars % COUNT_BREAK) + COUNT_BREAK);
		var newText = " [less than " + String(newCount) + " chars. left]";
		}
	else {var newText = " [<strong>Character count exceeded!</strong>]";}
	
	//output revised text to browser
	details.innerHTML = origNote + newText;
	
	return;
}