CKEditor is not full width of window

I have tried adding in - Cols="xx" however this does not work.

For reference, this is my function:

function update_textarea(value) {
$("#news_textarea textarea").each(function(index) {
message[index] = $(this).val();
var editor = $(this).ckeditorGet();
if (editor) {
editor.destroy()
}
});
document.getElementById('news_textarea').innerHTML='';
for(var i = 0; i < value; i++) {
if(message[i] || headline[i] || langs[i] && langs[i] != default_language)
{
document.getElementById('news_textarea').innerHTML+=' %headline% <input name="headline[]" type="text" value="'+headline[i]+'" size="80" onchange="headline['+i+']=this.value;" />';
document.getElementById('news_textarea').innerHTML+='<textarea name="message[' + i + ']" rows="20">'+message[i]+'</textarea><br /><br />';
}
else
{
message[i] = '';
headline[i] = '';
langs[i] = '';
document.getElementById('news_textarea').innerHTML+=' <b>%headline%: </b><br /> <input name="headline[]" type="text" value="" size="80" onchange="headline['+i+']=this.value;" /><hr />';
document.getElementById('news_textarea').innerHTML+='<textarea name="message[' + i + ']" rows="20"></textarea><br /><br />';
}
}
$("#news_textarea textarea").ckeditor();
if(message.length > value) {
var message_length = message.length;
for(var i = value; i < message_length; i++) {
delete message[i];
message.length--;
delete headline[i];
headline.length--;
delete langs[i];
langs.length--;
}
}

initialize_language();
update_language();
}

Hi typeof, I cannot publish a test of this as you have to be an admin on the site to view the ckeditor.

Just to clarify, it is the width of the ckeditor itself which is not filling the full width of the page. The information it posts is fine.