From dbf87ff5cd5132d6e0227c06feb8d21ad37013f4 Mon Sep 17 00:00:00 2001
From: Allan Jardine <allan.jardine@sprymedia.co.uk>
Date: Sat, 14 Jan 2012 09:48:52 +0000
Subject: [PATCH] Performance: MUCH faster removing of DOM elements in the
 header and body of the table - 8060 - performance testing:
 http://jsperf.com/remove-detach/11

---
 media/js/jquery.dataTables.js | 19 ++++++++++---------
 media/src/core/core.draw.js   | 19 ++++++++++---------
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/media/js/jquery.dataTables.js b/media/js/jquery.dataTables.js
index f78d1ece..d2acdc92 100644
--- a/media/js/jquery.dataTables.js
+++ b/media/js/jquery.dataTables.js
@@ -1184,7 +1184,7 @@
 		 */
 		function _fnDrawHead( oSettings, aoSource, bIncludeHidden )
 		{
-			var i, iLen, j, jLen, k, kLen;
+			var i, iLen, j, jLen, k, kLen, n, nLocalTr;
 			var aoLocal = [];
 			var aApplied = [];
 			var iColumns = oSettings.aoColumns.length;
@@ -1216,12 +1216,14 @@
 		
 			for ( i=0, iLen=aoLocal.length ; i<iLen ; i++ )
 			{
+				nLocalTr = aoLocal[i].nTr;
+				
 				/* All cells are going to be replaced, so empty out the row */
-				if ( aoLocal[i].nTr )
+				if ( nLocalTr )
 				{
-					for ( k=0, kLen=aoLocal[i].nTr.childNodes.length ; k<kLen ; k++ )
+					while( (n = nLocalTr.firstChild) )
 					{
-						aoLocal[i].nTr.removeChild( aoLocal[i].nTr.childNodes[0] );
+						nLocalTr.removeChild( n );
 					}
 				}
 		
@@ -1235,7 +1237,7 @@
 					 */
 					if ( aApplied[i][j] === undefined )
 					{
-						aoLocal[i].nTr.appendChild( aoLocal[i][j].cell );
+						nLocalTr.appendChild( aoLocal[i][j].cell );
 						aApplied[i][j] = 1;
 		
 						/* Expand the cell to cover as many rows as needed */
@@ -1274,7 +1276,7 @@
 		 */
 		function _fnDraw( oSettings )
 		{
-			var i, iLen;
+			var i, iLen, n;
 			var anRows = [];
 			var iRowCount = 0;
 			var iStripes = oSettings.asStripeClasses.length;
@@ -1431,10 +1433,9 @@
 				if ( !oSettings.oScroll.bInfinite || !oSettings._bInitComplete ||
 				 	oSettings.bSorted || oSettings.bFiltered )
 				{
-					nTrs = oSettings.nTBody.childNodes;
-					for ( i=nTrs.length-1 ; i>=0 ; i-- )
+					while( (n = oSettings.nTBody.firstChild) )
 					{
-						nTrs[i].parentNode.removeChild( nTrs[i] );
+						oSettings.nTBody.removeChild( n );
 					}
 				}
 				
diff --git a/media/src/core/core.draw.js b/media/src/core/core.draw.js
index df7d5600..22ff1504 100644
--- a/media/src/core/core.draw.js
+++ b/media/src/core/core.draw.js
@@ -215,7 +215,7 @@ function _fnBuildHead( oSettings )
  */
 function _fnDrawHead( oSettings, aoSource, bIncludeHidden )
 {
-	var i, iLen, j, jLen, k, kLen;
+	var i, iLen, j, jLen, k, kLen, n, nLocalTr;
 	var aoLocal = [];
 	var aApplied = [];
 	var iColumns = oSettings.aoColumns.length;
@@ -247,12 +247,14 @@ function _fnDrawHead( oSettings, aoSource, bIncludeHidden )
 
 	for ( i=0, iLen=aoLocal.length ; i<iLen ; i++ )
 	{
+		nLocalTr = aoLocal[i].nTr;
+		
 		/* All cells are going to be replaced, so empty out the row */
-		if ( aoLocal[i].nTr )
+		if ( nLocalTr )
 		{
-			for ( k=0, kLen=aoLocal[i].nTr.childNodes.length ; k<kLen ; k++ )
+			while( (n = nLocalTr.firstChild) )
 			{
-				aoLocal[i].nTr.removeChild( aoLocal[i].nTr.childNodes[0] );
+				nLocalTr.removeChild( n );
 			}
 		}
 
@@ -266,7 +268,7 @@ function _fnDrawHead( oSettings, aoSource, bIncludeHidden )
 			 */
 			if ( aApplied[i][j] === undefined )
 			{
-				aoLocal[i].nTr.appendChild( aoLocal[i][j].cell );
+				nLocalTr.appendChild( aoLocal[i][j].cell );
 				aApplied[i][j] = 1;
 
 				/* Expand the cell to cover as many rows as needed */
@@ -305,7 +307,7 @@ function _fnDrawHead( oSettings, aoSource, bIncludeHidden )
  */
 function _fnDraw( oSettings )
 {
-	var i, iLen;
+	var i, iLen, n;
 	var anRows = [];
 	var iRowCount = 0;
 	var iStripes = oSettings.asStripeClasses.length;
@@ -462,10 +464,9 @@ function _fnDraw( oSettings )
 		if ( !oSettings.oScroll.bInfinite || !oSettings._bInitComplete ||
 		 	oSettings.bSorted || oSettings.bFiltered )
 		{
-			nTrs = oSettings.nTBody.childNodes;
-			for ( i=nTrs.length-1 ; i>=0 ; i-- )
+			while( (n = oSettings.nTBody.firstChild) )
 			{
-				nTrs[i].parentNode.removeChild( nTrs[i] );
+				oSettings.nTBody.removeChild( n );
 			}
 		}