Merge pull request #346 from OliverEngineer/experimental

attempting fix for issue 305

web/js/asyncCommand.js

+function pronterfaceWebInterface_setup(){
+	pronterfaceWebInterface_attachAsync();
+}
+
+function pronterfaceWebInterface_attachAsync(){
+	
+	var list = [];
+	if(document.getElementsByClassName){
+		list = document.getElementsByClassName('command');
+	}else if(document.getElementsByTagName){
+		list = document.getElementsByTagName('a');
+		list.concat( document.getElementsByTagName('area') );
+		//TODO filter list via checking the className attributes
+	}else{
+		console && console.error && console.error('unable to gather list of elements');
+		return false;
+	}
+	
+	for(var i=0; i < list.length; i++){
+		list[i].addEventListener && list[i].addEventListener( 'click', function(e){return pronterfaceWebInterface_asyncCommand(null, e);}, true );
+		list[i].attachEvent && list[i].attachEvent( 'onclick', function(e){return pronterfaceWebInterface_asyncCommand(null, e);} );
+	}
+	
+	return true;
+}
+
+
+function pronterfaceWebInterface_asyncCommand( urlOrElement, event ){
+
+	if( ! urlOrElement && event.target)
+		urlOrElement = event.target;
+
+	var url = null;
+	if( typeof urlOrElement == 'string' ){
+		url = urlOrElement;
+	}else{
+		url = urlOrElement&&urlOrElement.href;
+	}
+
+	if( typeof url != 'string' ){
+		console && console.error && console.error('url not a string', urlOrElement, url);
+		return true;
+	}
+
+	var httpRequest;
+	if (window.XMLHttpRequest) { // Mozilla, Safari, ...
+		httpRequest = new XMLHttpRequest();
+	} else if (window.ActiveXObject) { // IE 8 and older
+		httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
+	}
+	
+	if( ! httpRequest ){
+		alert('no AJAX available?');
+		// follow link
+		return true;
+	}
+	
+	//onreadystatechange
+	//onerror
+	httpRequest.open( 'GET', url, true);
+	httpRequest.send(null);
+	
+	// don't follow link
+	if( event ){
+		event.stopImmediatePropagation && event.stopImmediatePropagation();
+		event.defaultPrevented = true;
+		event.preventDefault && event.preventDefault();
+	}
+	return false;
+}
+
+
+if (document.addEventListener) {
+    document.addEventListener("DOMContentLoaded", pronterfaceWebInterface_setup, false);
+} else if (document.attachEvent) {
+    document.attachEvent("onreadystatechange", pronterfaceWebInterface_setup);
+} else {
+    document.onload = pronterfaceWebInterface_setup;
+}