Combinando due variabili per impostare una nuova variabile su una variabile già dichiarata usando JavaScript

Question

Sto cercando di impostare una nuova variabile sullo stesso valore di una variabile già dichiarata combinando due variabili che insieme rendono il nome della variabile originale ... questo può sembrare confuso, quindi ecco un esempio:

// JavaScript Document


document.write (finalVar);

$(document).ready(function()
{ 
 var position_1 = $("#box_1").position();
 var left_1 = position_1.left;
 var top_1 = position_1.top;
 var position_2 = $("#box_2").position();
 var left_2 = position_2.left;
 var top_2 = position_2.top;
 var box;
 var boxLength;
 var boxNumber;
 var selected = 0;


 $("#box_1").click
    (function()
        {
            if (selected == 1) // if a box is selected run the following
                {       
                    box = $(".selected").attr("id");
                    boxLength = box.length;
                    boxNumber = box.charAt(boxLength-1); // finds the number of the box
                    alert(+boxNumber);
                if (box == "box_1") // if the selected box is itself     then mimimise the box, remove the selected class from it and set selected to zero
                    {
                        $("#box_1").animate({height:50,opacity:0.8,left:left_1,top:top_1,borderRadius:4,MozborderRadiu  s:4},(60),"swing").animate({width:50},(60),"swing").animate({opacity:0.6},(150),        function()
                        {
                                $(this).removeClass("selected");
                        }); 
                    selected = 0;
                    }
                else
                    {
                        $(".selected").animate({height:50,opacity:0.8,left:left_+boxNumber,top:top_+boxNumber,borderRadius:4,MozborderRadius:4},(60),"swing").animate({width:50},(60),"swing").animate({opacity:0.6},(150),     function()
                        {
                            $(".selected").removeClass("selected");
                            $("#box_1").animate({width:900,left:60,top:0,borderRadius:10,MozborderRadius:10},(60),"swing").animate({height:500},(60),"swing").animate({opacity:1},(150), function()
                                {
                                    $("#box_1").addClass("selected");
                                });
                        }
                );} } // end of function for if a box is selected
            else // if no box is selected run the following
                {
                    $("#box_1").animate({width:900,left:60,top:0,borderRadius:10,MozborderRadius:10},(60),"swing").animate({height:500},(60),"swing").animate({opacity:1},(150), function()
                        {   
                            $("#box_1").addClass("selected");


                        }); 
                    selected = 1;
                }
        });

    $("#box_2").click
    (function()
        {
            if (selected == 1) // if a box is selected run the following
                {       
                    box = $(".selected").attr("id");
                    boxLength = box.length;
                    boxNumber = box.charAt(boxLength-1); // finds the number of the box
                    alert(+boxNumber);
                if (box == "box_2") // if the selected box is itself then mimimise the box, remove the selected class from it and set selected to zero
                    {
                        $("#box_2").animate({height:50,opacity:0.8,left:left_2,top:top_2,borderRadius:4,MozborderRadius:4},(60),"swing").animate({width:50},(60),"swing").animate({opacity:0.6},(150),  function()
                        {
                                $(this).removeClass("selected");
                            selected = 0;   
                        }); 
                    }
                else
                    {
                    $(".selected").animate({height:50,opacity:0.8,left:left_+boxNumber,top:top_+boxNumber,borderRadius:4,MozborderRadius:4},(60),"swing").animate({width:50},(60),"swing").animate({opacity:0.6},(150),     function()
                        {
                            $(".selected").removeClass("selected");
                            $("#box_2").animate({width:900,left:60,top:0,borderRadius:10,MozborderRadius:10},(60),"swing").animate({height:500},(60),"swing").animate({opacity:1},(150), function()
                                {
                                    $("#box_2").addClass("selected");
                                });
                        }
                );} } // end of function for if a box is selected
            else // if no box is selected run the following
                {
                    $("#box_2").animate({width:900,left:60,top:0,borderRadius:10,MozborderRadius:10},(60),"swing").animate({height:500},(60),"swing").animate({opacity:1},(150), function()
                        {   
                            $("#box_2").addClass("selected");
                            selected = 1;
                        }); 
                }
        });

});

Vorrei quindi che 5 fosse scritto al documento ... c'è un modo per farlo? So che questo probabilmente non è il modo corretto per iniziare a pensare di farlo, lo stavo solo usando come sinonimo di quello che stavo cercando di fare.

Grazie per l'aiuto.