Add httpRoot tip to http node

nodes/core/io/21-httpin.html

@@ -32,6 +32,7 @@
         <label for="node-input-name"><i class="icon-tag"></i> Name</label>
         <input type="text" id="node-input-name" placeholder="Name">
     </div>
+    <div id="node-input-tip" class="form-tips">The url will be relative to <code><span id="node-input-path"></span></code>.</div>
 </script>
 
 <script type="text/x-red" data-help-name="http in">
@@ -76,11 +77,30 @@
         outputs:1,
         icon: "white-globe.png",
         label: function() {
-            return this.name||(this.url?("["+this.method+"] "+this.url):"http");
+            if (this.name) {
+                return this.name;
+            } else if (this.url) {
+                var root = document.location.pathname.slice(0,-1);
+                root += this.url;
+                return "["+this.method+"] "+root;
+            } else {
+                return "http";
+            }
         },
         labelStyle: function() {
             return this.name?"node_label_italic":"";
+        },
+        oneditprepare: function() {
+            var root = document.location.pathname.slice(0,-1);
+            if (root == "") {
+                $("#node-input-tip").hide();
+            } else {
+                $("#node-input-path").html(root);
+                $("#node-input-tip").show();
             }
+            //document.getElementById("node-config-wsdocpath").innerHTML=
+        }
+
     });
 </script>