function calculate_price()
{
var form=document.forms[0];
var drop_downs=new Array();
drop_downs[0]=10;
var price=form.elements[4].value/1;
for (var i=0; i<drop_downs.length; i++)
	{
	var n=drop_downs[i];
	var dd=form.elements[n];
	var sel=dd.selectedIndex;
	var v=dd.options[sel].value;
	var ind=v.indexOf("_");
	if (ind>0)
		{
		var add_p=v.substring(ind+1)/1;
		price+=add_p;
		}
	}
price=display_price(price);
var c=document.getElementById("price_tag");
var txt=price+"";
var cTextNode=document.createTextNode(txt);
if (c.childNodes.length==0)
	{
	c.appendChild(cTextNode);
	}
else
	{
	var sNode=c.childNodes[0];
	//sNode.replaceNode(cTextNode);
	c.replaceChild(cTextNode, sNode);
	}
}

function display_price(p)
{
var ret_p="";
var pp=p+"";
var ind1=pp.indexOf('.');
if (ind1<0)
	{
	return (pp+".00");
	}
var whole=pp.substring(0,ind1);
var dec=pp.substring(ind1+1);
ch3='0';
if (dec.length>2)
	{
	var ch3=dec.charAt(2);
	}
if (dec.length==1)
	{
	dec=dec+'0';
	}
dec=dec.substring(0,2);
if (ch3/1>4)
	{
	if (dec/1<99)
		{
		dec=dec/1+1;
		}
	else
		{
		whole=whole/1+1;
		dec='00';
		}
	}
var ret_p=whole+"."+dec;
return ret_p;
}