var area;
var showDiv;
var formattedStr = "";
startPosition = 0;
var endPosition = 0;

window.onload = function()
{
	area = document.getElementById("posttekst");
	showDiv = document.getElementById("showDiv");
};

function insertsBoldTag()
{
	findPositions();

	var text = area.value;
	if (startPosition!=endPosition) {
		var sbStr = text.substring(startPosition,endPosition);
		sbStr = "[b]"+sbStr+"[/b]";

		fillsFormattedString(text,sbStr);
	}
}

function insertsItalicTag()
{
	findPositions();

	var text = area.value;
	if (startPosition!=endPosition) {
		var sbStr = text.substring(startPosition,endPosition);
		sbStr = "[i]"+sbStr+"[/i]";

		fillsFormattedString(text,sbStr);
	}
}

function insertsUnderlineTag()
{
	findPositions();

	var text = area.value;
	if (startPosition!=endPosition) {
		var sbStr = text.substring(startPosition,endPosition);
		sbStr = "[u]"+sbStr+"[/u]";

		fillsFormattedString(text,sbStr);
	}
}

function insertsDeleteTag()
{
	findPositions();

	var text = area.value;
	if (startPosition!=endPosition) {
		var sbStr = text.substring(startPosition,endPosition);
		sbStr = "[url]"+sbStr+"[/url]";

		fillsFormattedString(text,sbStr);
	}
}

function findPositions()
{
	var text = area.value;

	if (document.selection) {
		// Internet Explorer
		var range = document.selection.createRange();
		var dpl = range.duplicate();
		if (range.text.length > 0) {
			dpl.moveToElementText(area);
			dpl.setEndPoint("EndToEnd", range);
			startPosition = dpl.text.length-range.text.length;
			endPosition = startPosition + range.text.length;
		}
	}
	else {
		// Mozilla Firefox
		startPosition = area.selectionStart;
		endPosition = area.selectionEnd;
	}
}

function fillsFormattedString(text, selectedText)
{
	// split textarea value into three pieces: before startPosition,
        // startPosition until endPosition, and after endPosition
	var str1 = text.substring(0,startPosition);
	var str2 = text.substring(startPosition,endPosition);
	var str3 = text.substring(endPosition,text.length);

	// replace str2 with formatted substring (selectedText)
	str2 = selectedText;
	// form the new string
	formattedStr = str1+str2+str3;
	area.value = formattedStr;
}