// load multiple functions on page load
function addLoadEvent(func)
{
	var oldonload = window.onload;
	if(typeof window.onload != "function")
	{
		window.onload = func;
	}
	else
	{
		window.onload = function()
		{
			oldonload();
			func();
		}
	}
}

function checkChecks(){
if(!document.getElementsByTagName('input'))
{
	return false;
}
else
{
	var theChecks = document.getElementsByTagName('input');

	var i;

	for(i = 0; i < theChecks.length; i++)
	{
		var thisCheck = theChecks[i];
				
		if(thisCheck.checked==true)
		{
			var li = document.getElementById("li_"+thisCheck.value);
			li.className += " selected";
		}			
	}
}
}

//var total = 0;

// checkbox handling
function handleChecks(checkBoxName){

	var theChecks = document.getElementsByTagName('input');
	var i;
	for(i = 0; i < theChecks.length; i++)
	{	
		if(theChecks[i].type == "checkbox")
		{
			var thisCheck = theChecks[i];
						
			thisCheck.onclick = function()
			{							
	            var li = document.getElementById("li_"+this.value);
           
					if(this.checked)
					{
						addSampleXmlHTTP(this,"");
						li.className += " selected";						
					}
					else
					{
						this.checked = false;
						li.className = li.className.replace(/selected/g,"");
						addSampleXmlHTTP(this,"remove");				
					}		
			}				
		}			
	}
}

addLoadEvent(handleChecks);
addLoadEvent(checkChecks);

/******************************
	Add sample
******************************/

function addSampleXmlHTTP(checkbox,action){

var xmlhttp=false;
        try {
                xmlhttp = new ActiveXObject('Msxml2.XMLHTTP');
        } catch (e) {
                try {
                        xmlhttp = new ActiveXObject('Microsoft.XMLHTTP');
            } catch (E) {
                xmlhttp = false;
                        }
        }
        if (!xmlhttp && typeof XMLHttpRequest!='undefined')
        {
                xmlhttp = new XMLHttpRequest();
        }
        
        var id = checkbox.id;
        //console.log(id);
        var file = '/scripts/addsample.php?id='+id+'&action='+action;
        
		xmlhttp.open('GET', file, true);
		
		xmlhttp.onreadystatechange=function()
		{
			if (xmlhttp.readyState==4)
			{
                var content = xmlhttp.responseText;
                if(content)
                {
					var li = checkbox.parentNode.parentNode;				
					if(content > 0)
					{
						checkbox.checked = false;
						li.className = li.className.replace(/selected/g,"");
						alert("You have already selected four samples. Your last selection has not been added to your total chosen.");					
					}
				}
        	}
        }
        xmlhttp.send(null);
return;
}