Unite two variables in document.write javascript -

Unite two variables in document.write javascript -

i have 2 variables:

var = 'aaa'; var b = 'bbb';

i output them using 1 document.write like:

aaabbb

how unite them in document.write? need $a.$b in php.

nobody forbids utilize + (can used concatenate strings) :)

document.write(a+b)

another variant

document.write(a.concat(b))

javascript document.write