Is there a JavaScript function that can pad a string to get to a determined length?

Question

I am in need of a JavaScript function which can take a value and pad it to a given length (I need spaces, but anything would do). I found this:

Code:

Answer 1

Taking up Samuel's ideas, upward here. And remember an old SQL script, I tried with this:

a=1234;
'0000'.slice(a.toString().length)+a;

It works in all the cases I could imagine:

a=     1 result  0001
a=    12 result  0012
a=   123 result  0123
a=  1234 result  1234
a= 12345 result 12345
a=  '12' result  0012