How are you "passing" this arrar to PHP? As a function parameter, hidden variable, or what? Combining PHP and JS can be tricky at best, since you are mixing server vs. client side stuff.
I don't know about JS arrays, but PHP arrays are just like C. The array would break down as:
[0] = 'K'
[1] = 'I'
[2] = 'N'
[3] = 'G'
HTH.