function submitCode()
{
    document.forms["code"].submit();
    var x = document.getElementById("status");
    x.innerHTML = "<strong>Checking answer ...</strong>";
    x = document.getElementById("check");
    x.disabled = true;
    x.value = "Checking Answer ...";
    document.getElementById("skip").disabled = true;
}

function setSelectionRange(input, selectionStart, selectionEnd) 
{
    if (input.setSelectionRange) 
    {
	input.focus();
	input.setSelectionRange(selectionStart, selectionEnd);
    }
    else if (input.createTextRange) 
    {
	var range = input.createTextRange();
	range.collapse(true);
	range.moveEnd('character', selectionEnd);
	range.moveStart('character', selectionStart);
	range.select();
    }
}

function replaceSelection (input, replaceString) 
{
    if (input.setSelectionRange) 
    {
	var selectionStart = input.selectionStart;
	var selectionEnd = input.selectionEnd;
	input.value = input.value.substring(0, selectionStart)+ replaceString + input.value.substring(selectionEnd);
	if (selectionStart != selectionEnd)
	{ 
	    setSelectionRange(input, selectionStart, selectionStart + 	replaceString.length);
	}
	else
	{
	    setSelectionRange(input, selectionStart + replaceString.length, selectionStart + replaceString.length);
	}
    }
    else if (document.selection) 
    {
	var range = document.selection.createRange();
	if (range.parentElement() == input) 
	{
	    var isCollapsed = range.text == '';
	    range.text = replaceString;
	    if (!isCollapsed)  
	    {
		range.moveStart('character', -replaceString.length);
		range.select();
	    }
	}
    }
}

function catchTab(item,e)
{
    if(navigator.userAgent.match("Gecko"))
    {
	c=e.which;
    }
    else
    {
	c=e.keyCode;
    }
    if(c==9)
    {
	replaceSelection(item,String.fromCharCode(9));
	setTimeout("document.getElementById('"+item.id+"').focus();",0);	
	return false;
    }
}

var lineObjOffsetTop = 2;

function addLineNumbers(id)
{
    var el = document.createElement('DIV');
    var ta = document.getElementById(id);
    var content = document.getElementById('snippet').value;
    ta.parentNode.insertBefore(el,ta);
    el.appendChild(ta);
    el.className='textAreaWithLines';
    el.style.width = (ta.offsetWidth + 30) + 'px';
    ta.style.position = 'absolute';
    ta.style.left = '30px';
    el.style.height = (ta.offsetHeight + 2) + 'px';
    el.style.overflow='hidden';
    el.style.position = 'relative';
    el.style.width = (ta.offsetWidth + 30) + 'px';
    var lineObj = document.createElement('DIV');
    lineObj.style.position = 'absolute';
    lineObj.style.top = lineObjOffsetTop + 'px';
    lineObj.style.left = '0px';
    lineObj.style.width = '27px';
    el.insertBefore(lineObj,ta);
    lineObj.style.textAlign = 'right';
    lineObj.className='lineObj';
    var string = '';
    split_content = content.split('\n');
    if(id == "answer")
    {
		for(var no=split_content.length+1;no<1000;no++)
		{
			if(string.length>0)string = string + '<br>';
			string = string + no;
		}
	}
	else
	{
		for(var no=1;no<=split_content.length;no++)
		{
			if(string.length>0)string = string + '<br>';
			string = string + no;
		}
	}
	ta.onmousedown = function() { positionLineObj(lineObj,ta); };
    ta.onscroll = function() { positionLineObj(lineObj,ta); };
    ta.onblur = function() { positionLineObj(lineObj,ta); };
    ta.onfocus = function() { positionLineObj(lineObj,ta); };
    ta.onmouseover = function() { positionLineObj(lineObj,ta); };
    lineObj.innerHTML = string;
}
       
function positionLineObj(obj,ta)
{
    obj.style.top = (ta.scrollTop * -1 + lineObjOffsetTop) + 'px';  
}