Boosting Javascript Performance Tips

Tip1
define local variables
When any variable is referenced, Javascript looks it up by looping through different members of the set of variables. The deeper the engine has to look for a variable in this scope chain, the longer it will take. The search starts with the local variables and then moves to the global variables.Therefore it’s always better to redefine global variables locally.

Tip2
Do not use with() statement
with() statement gives local variables the performance drawbacks of global ones, but in return it derails Javascript optimization. with() appends extra set of variables to the beginning of the scope chain. So anytime a variable is called, the Javascript engine has to loop through the with() variables, then goes to the local variables, and then the global variables.