define optional parametr parentID for tooltip element

src/core.js

@@ -60,7 +60,6 @@ nv.render = function render(step) {
 };
 nv.render.queue = [];
 
-
 nv.addGraph = function(obj) {
   if (typeof arguments[0] === 'function')
     obj = {generate: arguments[0], callback: arguments[1]};
@@ -70,17 +69,13 @@ nv.addGraph = function(obj) {
   if (!nv.render.active) nv.render();
 };
 
-
 nv.identity = function(d) { return d };
 
-
-nv.strip = function(s) {
-  return s.replace(/(\s|&)/g,'');
-}
+nv.strip = function(s) { return s.replace(/(\s|&)/g,''); };
 
 function daysInMonth(month,year) {
   return (new Date(year, month+1, 0)).getDate();
-}
+};
 
 function d3_time_range(floor, step, number) {
   return function(t0, t1, dt) {
@@ -97,19 +92,16 @@ function d3_time_range(floor, step, number) {
     }
     return times;
   };
-}
-
+};
 
 d3.time.monthEnd = function(date) {
   return new Date(date.getFullYear(), date.getMonth(), 0);
 };
 
-
 d3.time.monthEnds = d3_time_range(d3.time.monthEnd, function(date) {
     date.setUTCDate(date.getUTCDate() + 1);
     date.setDate(daysInMonth(date.getMonth() + 1, date.getFullYear()));
   }, function(date) {
     return date.getMonth();
   }
-);
-
+);

src/tooltip.js

@@ -8,7 +8,9 @@
 
   var nvtooltip = window.nv.tooltip = {};
 
-  nvtooltip.show = function(pos, content, gravity, dist) {
+  nvtooltip.show = function() {
+    var args = arguments;
+    var pos = args[0], content = args[1], gravity = args[2], dist = args[3], parentId = args[4];
 
     var container = document.createElement("div");
         container.className = "nvtooltip";
@@ -16,7 +18,7 @@
     gravity = gravity || 's';
     dist = dist || 20;
 
-    var body = document.getElementsByTagName("body")[0];
+    var body = parentId ? document.getElementById(parentId) : document.getElementsByTagName("body")[0];
 
     container.innerHTML = content;
     container.style.left = 1;