Javascript consuming variables when variable a = variable b
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I have a script setup like this (http://jsfiddle.net/YD66s/):


    var countFull = new Array(0,1,2,3,4,5,6);
    var countActive = new Array(0,1,2,3,4,5,6);

    function pickRandom(a) {
      if(arguments[1].length == 0) {
          arguments[1] = arguments[0];
      }
      
      var m = Math.floor(Math.random()*arguments[1].length);
      chosen = arguments[1].splice(m,1);
 
      return chosen;
    }

    setInterval(function() {
      pickRandom(countFull,countActive);
    }, 1000);

When I run this I want the variable to be set for that function only. Instead it is affecting countFull towards the end because I make arguments[1] = arguments[0]. How in javascript can I just reference a variable but not consume it and ultimately arguments[1] becomes arguments[0].

Hope this makes sense. This is driving me nuts how different javascript variables are compared to other languages like PHP.