From: brion <brion@smidge.(none)>
Date: Sun, 9 Aug 2009 00:54:57 +0000 (-0700)
Subject: Throttles updating of the character counter to reduce the performance impact on typin... 
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=c6d2e54a7159174736f0184b7b9bc8b7e08bb9df;p=quix0rs-gnu-social.git

Throttles updating of the character counter to reduce the performance impact on typing, especially on slower devices (mobiles, netbooks).

http://laconi.ca/trac/ticket/1462
---

diff --git a/js/util.js b/js/util.js
index 0ffa92ca92..440701937a 100644
--- a/js/util.js
+++ b/js/util.js
@@ -17,21 +17,41 @@
  */
 
 $(document).ready(function(){
+	var counterBlackout = false;
+	
 	// count character on keyup
 	function counter(event){
 		var maxLength = 140;
 		var currentLength = $("#notice_data-text").val().length;
 		var remaining = maxLength - currentLength;
 		var counter = $("#notice_text-count");
-		if (counter.text() != String(remaining)) {
-			counter.text(remaining);
-		}
+		
+		if (remaining.toString() != counter.text()) {
+		    if (!counterBlackout || remaining == 0) {
+                        if (counter.text() != String(remaining)) {
+                            counter.text(remaining);
+		        }
 
-		if (remaining < 0) {
-			$("#form_notice").addClass("warning");
-		} else {
-			$("#form_notice").removeClass("warning");
-		}
+                        if (remaining < 0) {
+                            $("#form_notice").addClass("warning");
+                        } else {
+                            $("#form_notice").removeClass("warning");
+                        }
+                        // Skip updates for the next 500ms.
+                        // On slower hardware, updating on every keypress is unpleasant.
+                        if (!counterBlackout) {
+                            counterBlackout = true;
+                            window.setTimeout(clearCounterBlackout, 500);
+                        }
+                    }
+                }
+	}
+	
+	function clearCounterBlackout() {
+		// Allow keyup events to poke the counter again
+		counterBlackout = false;
+		// Check if the string changed since we last looked
+		counter(null);
 	}
 
 	function submitonreturn(event) {