null variable problem

[gilgalbiblewheel]

I put a long script but the problem is small.
var book1 = bobj1.value;
var chapter1 = cobj1.value;
var verse1 = vobj1.value;
var book2 = bobj2.value;
var chapter2 = cobj2.value;
var verse2 = vobj2.value;

var bcvQuotes = new Array();
bcvQuotes[0] = "book1=";
bcvQuotes[1] = "&chapter1=";
bcvQuotes[2] = "&verse1=";
bcvQuotes[3] = "&book2=";
bcvQuotes[4] = "&chapter2=";
bcvQuotes[5] = "&verse2=";

var bcv = new Array();
bcv[0] = book1;
bcv[1] = chapter1;
bcv[2] = verse1;
bcv[3] = book2;
bcv[4] = chapter2;
bcv[5] = verse2;

var urlExtension = document.getElementById('displayurl');
var getKeyURL = "";
//var getKeyURL = "book1="+book1+"&chapter1="+chapter1+"&verse1="+verse1+"&book2="+book2+"&chapter2="+chapter2+"&verse2="+verse2;
urlExtension.innerHTML = "";
//urlExtension.innerHTML = "book1="+book1+"&chapter1="+chapter1+"&verse1="+verse1+"&book2="+book2+"&chapter2="+chapter2+"&verse2="+verse2;

for(a=0; a<bcv.length; a++){
if(bcv[a]!= ""){
getKeyURL += bcvQuotes[a] + bcv[a];
urlExtension += bcvQuotes[a] + bcv[a];
}
}
I don't know if this is written properly:
if(bcv[a]!= ""){

The reason this is happening is because the error shows:
Error: cobj1 is null
Source File: http://...twotexts/js/twotextstextareasample.js
Line: 163

[in2clearsky]

It might be because cobj1 isn't point to any object. Recheck your text box (i suppose) id/name. Or try to use getElementById(). If this doesn't help, just post a full code.

[gilgalbiblewheel]

It might be because cobj1 isn't point to any object. Recheck your text box (i suppose) id/name. Or try to use getElementById(). If this doesn't help, just post a full code.
Yeah you're right. I realized it after posting it. I'm using Ajax and the id wasn't parsed yet.
Here's the solved version:
function fillChapters1(){
var req = createRequest();
if(req){
req.onreadystatechange = function(){
var c = document.getElementById('showchapterdiv1');
if(req.readyState){
if(req.readyState == 4){
if(req.status == 200){
c.innerHTML = req.responseText;
}
}
}
}
var divIds = new Array();
divIds[0] = document.getElementById('showbookdiv1'); //not that it matters
divIds[1] = document.getElementById('showchapterdiv1');
divIds[2] = document.getElementById('showversediv1');
divIds[3] = document.getElementById('showbookdiv2');
divIds[4] = document.getElementById('showchapterdiv2');
divIds[5] = document.getElementById('showversediv2');

var urlExtension = document.getElementById('displayurl');

// var getKeyURL = "book1="+book1+"&chapter1="+chapter1+"&verse1="+verse1+"&book2="+book2+"&chapter2="+chapter2+"&verse2="+verse2;
// urlExtension.innerHTML = "book1="+book1+"&chapter1="+chapter1+"&verse1="+verse1+"&book2="+book2+"&chapter2="+chapter2+"&verse2="+verse2;

urlExtension.innerHTML = "";
var getKeyURL = "";

var bcv = new Array();
var bcvQuotes = new Array();

if(divIds[0].innerHTML!= 0){
bcvQuotes[0] = "book1=";
var bobj1 = document.getElementById('selbook1');
bcv[0] = bobj1.value;
urlExtension.innerHTML += bcvQuotes[0]+bcv[0];
getKeyURL += bcvQuotes[0]+bcv[0];
for(a=0; a<6; a++){
if(document.getElementById('txtarea_'+[a]).value!= ""){
getKeyURL += "&txtarea" + [a] + "=";
urlExtension.innerHTML += "&txtarea" + [a] + "=";
}
getKeyURL += document.getElementById('txtarea_'+[a]).value;
urlExtension.innerHTML += document.getElementById('txtarea_'+[a]).value;
}
}
if(divIds[1].innerHTML!= 0){
bcvQuotes[1] = "&chapter1=";
var cobj1 = document.getElementById('selchapter1');
bcv[1] = cobj1.value;
urlExtension.innerHTML += bcvQuotes[1]+bcv[1];
getKeyURL += bcvQuotes[1]+bcv[1];
}
if(divIds[2].innerHTML!= 0){
bcvQuotes[2] = "&verse1=";
var vobj1 = document.getElementById('selverse1');
bcv[2] = vobj1.value;
urlExtension.innerHTML += bcvQuotes[2]+bcv[2];
getKeyURL += bcvQuotes[2]+bcv[2];
}
if(divIds[3].innerHTML!= 0){
bcvQuotes[3] = "&book2=";
var bobj2 = document.getElementById('selbook2');
bcv[3] = bobj2.value;
urlExtension.innerHTML += bcvQuotes[3]+bcv[3];
getKeyURL += bcvQuotes[3]+bcv[3];
}
if(divIds[4].innerHTML!= 0){
bcvQuotes[4] = "&chapter2=";
var cobj2 = document.getElementById('selchapter2');
bcv[4] = cobj2.value;
urlExtension.innerHTML += bcvQuotes[4]+bcv[4];
getKeyURL += bcvQuotes[4]+bcv[4];
}
if(divIds[5].innerHTML!= 0){
bcvQuotes[5] = "&verse2=";
var vobj2 = document.getElementById('selverse2');
bcv[5] = vobj2.value;
urlExtension.innerHTML += bcvQuotes[5]+bcv[5];
getKeyURL += bcvQuotes[5]+bcv[5];
}
req.open("GET","getChapters1.php?"+getKeyURL,true);
req.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
req.send(null);
}
}
But I wonder if it would be possible to shrink this code with a for loop? It works as it is but the js page has this times 6, meaning in 6 functions.