JavaScript - Looping Through Arrays: For/in Vs Using Array Length

<SCRIPT LANGUAGE = "JAVASCRIPT">
var contestantNamesArray = ['Tom and Nazia', 'Pat and Dan', 'Sandra and Kofi', 'Ian and Adele', 'Paul and Costas'];

var judgesPointsArray = [2,1,5,4,3];
var audiencePointsArray = [4,5,2,3,1];

//code to declare a new array to store the combined points for each couple
var combinedPointsArray=new Array();

//code to calculate the combined points for each couple and store it in the combined points array

for (i = 0; i <= 4; i++)
{
combinedPointsArray[i] = judgesPointsArray[i] + audiencePointsArray[i];

//code to find  and output the maximum value in the combined points array
}

var winner = [0]; //set first pair as default winner
for (i = 1; i <= 4; i++)
{ //start with second pair
if (combinedPointsArray[i] => combinedPointsArray[winner[0]])
{ //compare to first in the winners
winners = [i]; //new high score
}else if (combinedPointsArray[winner] == combinedPointsArray[i])
{
winners[winners.length] = i;//add to highest tie
}
//danceoff between all numbers in winner array
}//for

for(i=0;i<winners.length;i++){
document.write(winners[i]+", ");
document.write(i);
} 
</SCRIPT>

array[1][1] = "ID[56]NAME[Hello World]START[10]";

ID[1][1] = 56;
Name[1][1] = "Hello World";
Start[1][1] = 20;

var salesPerson=new Array(100)
for (i=0; i <=100; i++)
{
	salesPerson[i]=new Array(2);	
}

var x = 0;

do
{
 
salesPerson[x][0] = getName();
salesPerson[x][1] = getSales();
x++;
}while(x != 100 && confirm("Enter more employee information?"));

printRow(salesPerson[][]);

function getName()
{
	var nameEntered = prompt("What is your first name?");
	return nameEntered;
}

function getSales()
{	
	var error;
	var salesEntered;
	
	do
	{
	 	salesEntered = prompt("What were your sales?");
	 	error = false;	 	 	
		if (isNaN(salesEntered) || salesEntered == null || salesEntered == "") error = true;			
	}while(error);	
	
	return salesEntered;
}

function printRow(salesPerson[][])
{
	for (i =0; i<salesPerson.length; i++)
	{
		document.write(salesPerson[i][0] + "     " + salesPerson[i][1]);
	}

}

		var field = new Array();
	var string0 = "..@@@@@..............."
	var string1 = "..@@@@@@........@@@..."
	var string2 = ".....@@@@@......@@@..."
	var string3 = ".......@@@@@@@@@@@@..."
	var string4 = ".........@@@@@........"
	var string5 = ".........@@@@@........"

	for (var i = 0; i < 6; i++) {
		field[i] = new Array();
		field[i] = eval("string" + i + ".slice('')");
	}
	document.write("field's type is " + typeof field + "<br>"); // object? but it should be explicit array
	document.write(typeof field[1])  // string? it should explicitly be an array, then it was filled with array elements
	document.write(typeof field[1][2]); // string - ok, I understand this bit
	document.write(field[1].length);
	document.write("<br>");
	
	for (var i = 0; i < field.length; i++) {
		field[i] = new Array();
		for (var k = 0; k < eval("string" + i + ".length"); k++) {
			field[i][k] = eval("string" + i + ".charAt(" + k + ")");
		}
		document.write("<br>");
	}
	
	document.write("field's type is " + typeof field + "<br>"); // seriously, an object?
	document.write(typeof field[1]) // why is this an object instead of an array?
	document.write(typeof field[1][2]); // string, yeah, I understand this as well
	document.write(field[1].length);
	document.write("<br>");

newField = field;
//for loops
newField[i][k] = 0; // does nothing, newField's elements remain the same.

<script type='text/javascript'> 
function iHistory() {
var hist=history.length;
if (hist>1)
	{
		parent.window.location = "orderentry.php";
	}
}
</script>

function display_form(id) {
	//Create some variables
	var html = "";
	var container = "form_container";
	var menu = load_menu(id, false);

	//Get id
	 for ( var i = 0; i < menu.length; i++ ) {  
		alert(i);
	}
	
	http = getHTTPObject();
	http.onreadystatechange = function() {
		if ( http.readyState == 4 && http.status == 200 ) {
			document.getElementById(container).innerHTML = http.responseText;
		} else {
			document.getElemenyById(container).innerHTML = "Loading...";
		}
	}
	http.open( "GET", "includes/forms.php?form=" + id );
	http.send();
		
	//Watch input fields 
	//login_listener();
}/*

function load_menu(menu, return_d) {
	//Availible menus
	var data = [];
	data [ 'login' ] = [ 'Login', 'Register', 'Recovery' ];
	data [ 'settings' ] = [ 'Profile', 'Account', 'something' ];
	
	 if (return_d == false) {
		return data[ menu ]; 
	} else {
		//Menu container ID's
		var cons = Array('menuitem1','menuitem2','menuitem3');
	
		for ( var i = 0; i < cons.length; i++ ) {
			document.getElementById(cons[i]).innerHTML += data[ menu ] [ i ];
		}
	}
}

\n

if(textareaname.value.length < 200)

if( strlen($_POST['textareaname']) < 200 )

function Foo () {
  this.args = Array.prototype.join.call (arguments);
}

var args = ["arg0", "arg1", "arg2"];

new Foo.apply (null, args);

new (Foo.apply (null, args));

(new Foo).apply (null, args);

var phone = document.getElementById('phone');

if(isNumericdashes(phone, "Please enter a valid phone number")){
									return true;
									}

function isNumericdashes(elem, helperMsg){
	var numericExpression = /^[0-9\(\)-]+$/;
	if(elem.value.match(numericExpression) &&(elem.length > 9)){
		return true;
	}else{
		alert(helperMsg);
		elem.focus();
		return false;
	}
}