var counter = 0;
function wave_rank_chart()
{
	if(counter % 2 == 0)
	{
		var asyn;
		if (window.XMLHttpRequest)
		{// code for IE7+, Firefox, Chrome, Opera, Safari
			asyn=new XMLHttpRequest();
		}
		else
		{// code for IE6, IE5
			asyn=new ActiveXObject("Microsoft.XMLHTTP");
		}
		
		asyn.onreadystatechange=function()
		{
			if (asyn.readyState==4 && asyn.status==200)
			{
				document.getElementById("wave_rank_chart").innerHTML= asyn.responseText;
			}
		}	
		asyn.open("GET", "wave_rank.php", true);
		asyn.send();
	}
	else
	{
		document.getElementById("wave_rank_chart").innerHTML= "";
	}
	counter++;
}