function insertbbcode(tekstarea, typebb) { 

switch (typebb){
	case "url": 
		var adres= prompt('Waar wilt u naartoe linken?', 'http://');
		break;
	case "img": 
		var adres= prompt('Welke afbeelding wilt u neerzetten?', 'http://');
		break;
}

function isUrl(s) {
	var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/
	return regexp.test(s);
}

			//IE support
			if (document.selection) {
				tekstarea.focus();
				sel = document.selection.createRange();
				switch (typebb){
					case "url":
						if(!isUrl(adres)){
							alert("De URL die u heeft ingevuld is NIET correct. De http:// dient te blijven staan. Probeert u het nog eens.");
							sel.text=sel.text;
							}
						else {
							if(sel.text=="") {
								 sel.text = "[URL]" + adres + "[/URL]"; 
							}
							else {
								 sel.text = "[URL=" + adres + "]" + sel.text + "[/URL]";
							}
						} 
						
						break;
					case "b": 
						sel.text = "[b]" + sel.text + "[/b]";
						break;
					case "u": 
						sel.text = "[u]" + sel.text + "[/u]";
						break;
					case "i": 
						sel.text = "[i]" + sel.text + "[/i]";
						break;
					case "img": 
						sel.text = "[img]" + adres + "[/img]" + sel.text;
						break;
					default:
						var adres = ' ';
				}
			}
	
			//MOZILLA/NETSCAPE support
			else if (tekstarea.selectionStart || tekstarea.selectionStart == '0') {
				var startPos = tekstarea.selectionStart;
				var endPos = tekstarea.selectionEnd;
				var selection = "";
				switch (typebb){
					case "url":
						if(!isUrl(adres)){
							alert("De URL die u heeft ingevuld is NIET correct. De http:// dient te blijven staan. Probeert u het nog eens.");
							selection = tekstarea.value.substring(startPos, endPos);
							}
						else {
								selection = "[url=" + adres + "]" +  tekstarea.value.substring(startPos, endPos) + "[/url]";
						} 
						break;
					case "b": 
						selection = "[b]" +  tekstarea.value.substring(startPos, endPos) + "[/b]";
						break;
					case "u": 
						selection = "[u]" +  tekstarea.value.substring(startPos, endPos) + "[/u]";
						break;
					case "i": 
						selection = "[i]" +  tekstarea.value.substring(startPos, endPos) + "[/i]";
						break;
					case "img": 
						selection = "[img]" + adres + "[/img]" + tekstarea.value.substring(startPos, endPos);
						break;
					default:
						selection = tekstarea.value.substring(startPos, endPos);
				}
				tekstarea.value = tekstarea.value.substring(0, startPos)
				+ selection
				+ tekstarea.value.substring(endPos, tekstarea.value.length);
			} else {
				tekstarea.value += tekstarea.value;
			}
	 
}


function ismaxlength(obj){
var mlength=obj.getAttribute? parseInt(obj.getAttribute("maxlength")) : ""
if (obj.getAttribute && obj.value.length>mlength)
obj.value=obj.value.substring(0,mlength)
}