Replace getElementsByClassName with querySelectorAll.
Replace getElementsByClassName with querySelectorAll.

getElementsByClassName returns an expensive live collection, whereas querySelectorAll returns a readonly snapshot that is lighterweight and faster.

KirillOsenkov/SourceBrowser,akrisiun/SourceBrowser,KirillOsenkov/SourceBrowser,akrisiun/SourceBrowser,KirillOsenkov/SourceBrowser,KirillOsenkov/SourceBrowser,akrisiun/SourceBrowser,akrisiun/SourceBrowser