check for array : isArray

$(document).ready(function(){
       var x = [];
       var y = [1,2,3];
       var z = 1;
     $("#result").text('Variable x is an array : ' + $.isArray(x));
      $("#result").append('<br/>' + 'Variable y is an array : ' + $.isArray(y) + '<br/>'); 
      $("#result").append('Variable z is an array : ' + $.isArray(z));
    });