Take JS array send by form

Hi I faced following problem: I've a form where which could have one or more input text fields (it is not clear how many they will be - one or more). Thay have same name - pn - and if they are more that one JavaScript treat them as an array - pn[x] The problem is that when I receive this form with more than one field - i.e. pm[2] - in my php script only the last value is seen, others are lost i.e. I loose pn[0], pn[1] and receive only pn[2] as a *pn* variable. I mean that it is NOT an array at all. What's the problem and how could I solve it? Thank you Ivo