Beginning JavaScript with DOM Scripting and Ajax, 2nd Edition

Chapter 2 ■ Data and Decisions
var arrayOne = new Array( "One", "Two", "Three","Four", "Five" );
var arrayTwo = new Array( "ABC", "DEF", "GHI" );
var arrayThree = new Array( "John", "Paul", "George","Ringo" );
var joinedArray = arrayOne.concat( arrayTwo, arrayThree );
document.write( "joinedArray has " + joinedArray.length + " elements" );
document.write( joinedArray[0] + "" )
document.write( joinedArray[11] + "" )
The new array, joinedArray, has 12 items. The items in this array are the same as they were in each of the
previous arrays; they’ve simply been concatenated together. The original arrays remain untouched.
Converting an Array to a String and Back
Having data in an array is handy when you want to loop through it or select certain elements. However, when you
need to send the data somewhere else, you probably should convert that data to a string. You can do that by looping
through the array and adding each element value to a string. However, there is no need for that, because the Array
object has a method called join() that does that for you. The method takes a string as a parameter. This string will be
added in between each element.
var arrayThree = new Array( "John", "Paul", "George","Ringo" );
var lineUp=arrayThree.join( ', ' );
alert( lineUp );
The resulting string, lineUp, has the value "John, Paul, George, Ringo". The opposite of join() is split(),
which is a method that converts a string to an array.
var lineUp="John, Paul, George, Ringo";
var members=lineUp.split( ', ' );
alert( members.length );
Sorting an Array
The sort() method allows you to sort the items in an array into alphabetical or numerical order:
var arrayToSort = new Array( "Cabbage", "Lemon","Apple", "Pear", "Banana" );
arrayToSort.sort( );
document.write(arrayToSort[0] + "" );
document.write(arrayToSort[1] + "" );
document.write(arrayToSort[2] + "" );
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