function isNum(args)
{
args = args.toString();

if (args.length == 0)
return false;

for (var i = 0;  i<args.length;  i++)
{
	if ((args.substring(i,i+1) < "0" || args.substring(i, i+1) > "9") && args.substring(i, i+1) != ".")
		{
		return false;
		}
}

return true;

}


function changes()
{
	var aa = document.sqr.len.value;

	if(isNum(aa))
	{
		document.sqr.val.value = aa*aa;
	}
	else
	{
		aa = aa.substring(0,aa.length-1);
		document.sqr.len.value = aa;
	}
}

function circle()
{
	var aa = document.cir.rad.value;

	if(isNum(aa))
	{
	   document.cir.val.value = Math.PI*(aa*aa);
	   document.cir.val2.value = Math.PI*2*aa;

	}
	else
	{
		aa = aa.substring(0,aa.length-1);
		document.cir.rad.value = aa;
	}
}

function circle1()
{
	aa = document.cir.dia.value;

	if(isNum(aa))
	{
	   document.cir.rad.value = aa/2;
	   circle();
	}
}


function circle2()
{
	aa = document.cir.rad.value;

	if(isNum(aa))
	{
	   document.cir.dia.value = aa*2;
	   circle();
	}
}

function tri()
{
	var aa = document.tria.len1.value;
	var bb = document.tria.len2.value;

	if(isNum(aa) && isNum(bb))
	{
	   document.tria.val.value = (aa*bb)/2;
	}
	else
	{
		aa = aa.substring(0,aa.length-1);
		document.tria.len.value = aa;
	}
}

function etria()
{
	var aa = document.etri.len.value;

	if(isNum(aa))
	{
	   document.etri.val.value = (Math.sqrt(3)/4)*(aa*aa);
	}
	else
	{
		aa = aa.substring(0,aa.length-1);
		document.etri.len.value = aa;
	}
}


function para()
{
	var aa = document.par.len1.value;
	var bb = document.par.len2.value;

	if(isNum(aa) && isNum(bb))
	{
	   document.par.val.value = (aa*bb);
	}
	else
	{
		aa = aa.substring(0,aa.length-1);
		//document.par.len.value = aa;
	}
}

function trapa(varr,c)
{
	var aa = document.trap.len1.value;
	var bb = document.trap.len2.value;
	var cc = document.trap.len3.value;

	if(isNum(aa) && isNum(bb) && isNum(cc))
	{
	   var ss = parseFloat(aa)+parseFloat(bb);
	   document.trap.val.value = ((1/2)*parseFloat(cc)*ss);
	}
	else
	{
		if(c == "1" && !isNum(aa))
		{
			aa = aa.substring(0,aa.length-1);
			document.trap.len1.value = aa;
		}
		if(c == "2" && !isNum(bb))
		{
			bb = bb.substring(0,bb.length-1);
			document.trap.len2.value = bb;
		}
		if(c == "3" && !isNum(cc))
		{
			cc = cc.substring(0,cc.length-1);
			document.trap.len3.value = cc;
		}

	}
}


function secta(varr,c)
{
	var aa = document.sect.len1.value;
	var bb = document.sect.len2.value;

	if(isNum(aa) && isNum(bb))
	{
	   var ss = parseFloat(aa)+parseFloat(bb);
	   document.sect.val.value = (Math.PI*parseFloat(aa)*parseFloat(aa)*parseFloat(bb))/360;
	}
	else
	{
		if(c == "1" && !isNum(aa))
		{
			aa = aa.substring(0,aa.length-1);
			document.sect.len1.value = aa;
		}
		if(c == "2" && !isNum(bb))
		{
			bb = bb.substring(0,bb.length-1);
			document.sect.len2.value = bb;
		}
	}
}


function color(test)
{

//var ch ="background-color: "+test+"; width: 60px; height: 25px;";
//alert(ch);
	for(var j=1; j<10; j++)
	{
		if(j!=2 && j!=5 && j!=6 && j!=8 && j!=8 && j!=8 && j!=8)
		{
		var myI=document.getElementsByTagName("input").item(j);
		//myI.setAttribute("style",ch);
		myI.style.backgroundColor=test;
		}
	}
	for(var j=36; j<46; j++)
	{
		if(j==38 || j==42 || j==45)
		{
		var myI=document.getElementsByTagName("input").item(j);
		//myI.setAttribute("style",ch);
		myI.style.backgroundColor=test;
		}
	}

//myI.setAttribute("style","background-color: #F70808; width: 60px; height: 25px;");
}


function color1(test)
{
var myI=document.getElementsByTagName("table").item(0);
//myI.setAttribute("style",ch);
myI.style.backgroundColor=test;
}