Overwrite variable content javascript

Question

If you have a variable set with sensitive data:

var secretPassword = \'myPa$sW0rd\';

and you overwrite it:

secretPassword = \'0         


        

Answer 1

Does a javascript engine allocate new memory for the new data?

yes

is the data myPa$sW0rd potentially somewhere in unallocated memory still?

yes if no garbage collection cleaned it up

My main question is this: is there a way to guarantee that you overwrite the data? (ie zero it out or securely delete the data).

Not really, except if you play with the garbage collector. See related post

I wonder if looping through the characters in the string and resetting them that way would do it.

No

Edit : As pointed out by doldt, there is no real security threat even if the previous data is still somewhere in memory.