diff --git a/lib/less/browser.js b/lib/less/browser.js
index a9f577fd..9aeabba4 100644
--- a/lib/less/browser.js
+++ b/lib/less/browser.js
@@ -23,33 +23,43 @@ less.fileAsync = less.fileAsync || false;
 // Interval between watch polls
 less.poll = less.poll || (isFileProtocol ? 1000 : 1500);
 
+var dumpLineNumbers = /!dumpLineNumbers:(comments|mediaquery|all)/.exec(location.hash);
+if (dumpLineNumbers) {
+    less.dumpLineNumbers = dumpLineNumbers[1];
+}
+
 //
 // Watch mode
 //
-less.watch   = function () { return this.watchMode = true };
-less.unwatch = function () { return this.watchMode = false };
+less.watch   = function () {	
+	if (!less.watchMode ){		
+		less.env = 'development';
+		initRunningMode();
+	}
+	return this.watchMode = true 
+};
 
-if (less.env === 'development') {
-    less.optimization = 0;
+less.unwatch = function () {clearInterval(less.watchTimer); return this.watchMode = false; };
 
-    if (/!watch/.test(location.hash)) {
-        less.watch();
-    }
-    var dumpLineNumbers = /!dumpLineNumbers:(comments|mediaquery|all)/.exec(location.hash);
-    if (dumpLineNumbers) {
-        less.dumpLineNumbers = dumpLineNumbers[1];
-    }
-    less.watchTimer = setInterval(function () {
-        if (less.watchMode) {
-            loadStyleSheets(function (e, root, _, sheet, env) {
-                if (root) {
-                    createCSS(root.toCSS(), sheet, env.lastModified);
-                }
-            });
-        }
-    }, less.poll);
-} else {
-    less.optimization = 3;
+function initRunningMode(){
+	if (less.env === 'development') {		
+		less.optimization = 0;		
+		less.watchTimer = setInterval(function () {			
+			if (less.watchMode) {
+				loadStyleSheets(function (e, root, _, sheet, env) {
+					if (root) {
+						createCSS(root.toCSS(), sheet, env.lastModified);
+					}
+				});
+			}
+		}, less.poll);
+	} else {
+		less.optimization = 3;
+	}
+}
+
+if (/!watch/.test(location.hash)) {
+	less.watch();
 }
 
 var cache;
@@ -75,7 +85,6 @@ for (var i = 0; i < links.length; i++) {
     }
 }
 
-
 less.refresh = function (reload) {
     var startTime, endTime;
     startTime = endTime = new(Date);