myArray.join( [ separator ] ) in ECMAScript 262

Returns a string representation of the array, separated by the delimiter of your choice.

Arguments

nametypedescription
separator String [optional] The string to separate each el
Return Type
String

Description

Calls the toString() method of each value in the array, and joins them together with the seperator supplied. If separator is omitted, a single comma "," is used. If you want no separator between the values, specify an empty string "".
var words = [ 'The' , 'quick' , 'brown' , 'fox' ];

//The following statements are all true
words.join()        == "The,quick,brown,fox";
words.join(' ')     == "The quick brown fox";
words.join(' :: ')  == "The :: quick :: brown :: fox";
words.join('')      == "Thequickbrownfox";