Hey guys,

So we have this product, and it's really slow in IE. We've already applied a lot of the practices advised by the IE guys themselves (like this, and this), and try to sacrifice clean code for performance in the critical parts like DOM manipulation.

However, as you can see in this IE profiler screenshot..

Just "String" is the biggest offender. Almost 750ms of exclusive time.

Does this mean IE is spending 750ms just instantiating Strings? I also read this stuff on the Opera dev blog:

A build script can remove whitespace, comments, replace strings with Array lookups (to avoid MSIE creating a string object for every single instance of a string — even in conditions)

But no more info regarding this. Anyone can clarify? It seems like IE has to create a full String instance every time you have " " in your code, which could explain this, but I don't know what the array lookup optimization would look like. BTW- we don't really do much of string concatenation anywhere in the code.

The library we use is MooTools 1.2.4

Any suggestions will be appreciated! Thx