Merge branch 'feature-add-arrow' into develop

sortt.js

@@ -44,6 +44,41 @@ window.sortt=function(normsort,revsort,isdefault){
   window.location.replace(url.href);
 };
 
+//create global function with main routine
+function getArrow(normsort,revsort,isdefault){
+	//sortt [normsort] (revsort) (isdefault)
+
+	//arrows
+	var arrow_down = '⯆';  // U+2BC6
+	var arrow_up = '⯅';		 // U+2BC5
+
+  //normsort is needed
+  if (!(normsort)) return false;
+
+  //default values of optinal parameters
+  if (!(revsort)) revsort = "";
+
+	//get sort param from url
+  let url_sort = (new URL(window.location)).searchParams.get("sort");
+
+  if ((url_sort === null) && isdefault) {
+		//if sort is sorted as default add arrow tho this table header
+		if (isdefault) return arrow_down;
+	} else {
+		//if sort arg is in url test if it corelates with colum header sort arguments
+		if (url_sort === normsort) {
+			//the table is sorted with this header normal
+			return arrow_down;
+		} else if (url_sort === revsort) {
+			//the table is sorted with this header reverse
+			return arrow_up;
+		} else {
+			//the table is NOT sorted with this header
+			return false;
+		}
+	}
+}
+
 
 //USE Functions