Opened 9 years ago

Closed 9 years ago

#11372 closed enhancement (fixed)

dojo.addClass causes performance problems in IE6 and 7 by assigning identical CSS class

Reported by: Shane O'Sullivan Owned by: Eugene Lazutkin
Priority: high Milestone: 1.5
Component: Core Version: 1.5.0b2
Keywords: Cc:
Blocked By: Blocking:

Description (last modified by Shane O'Sullivan)

When dojo.addClass is called, and the resulting class string is identical to the class already on the node, it still modifies the class.

This causes severe performance issues in IE6 and 7, which I presume comes from forcing a redraw.

dojo.removeClass does not do this, and uses

if(node[_className] != cls){ node[_className] = cls; }

dojo.addClass should also do this. Performance tests have shown, when creating a TabContainer?, the average time for each dojo.addClass call goes from 14ms to 10ms, a huge saving

Instantiating a TabContainer? with many (> 30) tabs in IE 6 and 7 is very slow, and this one line fix speeds it up a lot.

Attachments (1)

dojo.addClass.patch​ (421 bytes) - added by Shane O'Sullivan 9 years ago.
Fix for this issue

Download all attachments as: .zip

Change History (4)

comment:1 Changed 9 years ago by Shane O'Sullivan

Description: modified (diff)

Changed 9 years ago by Shane O'Sullivan

Attachment: dojo.addClass.patch​ added

Fix for this issue

comment:2 Changed 9 years ago by Eugene Lazutkin

Owner: changed from anonymous to Eugene Lazutkin
Priority: high → normal
severity: major → minor
Status: new → assigned

comment:3 Changed 9 years ago by Eugene Lazutkin

Resolution: → fixed
Status: assigned → closed
Type: defect → enhancement

Robot missed: (In [22383]) Performance improvement for dojo.addClass(), thx shaneosullivan!, !strict, fixes #11372.

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