function InsertSingleTag(tag) {
  InsertDoubleTag("", " " + tag);
} InsertSingleTag

function InsertDoubleTag(startTag, endTag) {
  element = $("txaContent");
  
	if (document.selection) {
		element.focus();
		sel = document.selection.createRange();
		sel.text = startTag + sel.text + endTag;
	} else if (element.selectionStart || element.selectionStart == "0") {
		element.focus();
		var startTagPos = element.selectionStart;
		var endPos = element.selectionEnd;
		element.value = element.value.substring(0, startTagPos) + startTag + element.value.substring(startTagPos, endPos) + endTag + element.value.substring(endPos, element.value.length);
	} else {
		element.value += startTag + endTag;
	} //end if
	
	PreviewContent();
} //InsertDoubleTag

function PreviewContent() {
	$("site-content").innerHTML = $("txaContent").value;
} //PreviewContent