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 check(df)
{
	var ad = df.value;
	if(!isNum(ad))
	{
		if(ad != "")
			ad = ad.substring(0,ad.length-1);

		df.value = ad;
	}
}

var ai=4;
var aj=4;
var bi=4;
var bj=4;

function seta(xx1, xx2)
{
	if(xx1 == 1){ai = 4; aj = 4;}
	else if(xx1 == 2){ai = 4; aj = 3;}
	else if(xx1 == 3){ai = 3; aj = 4;}
	else if(xx1 == 4){ai = 4; aj = 2;}
	else if(xx1 == 5){ai = 2; aj = 4;}
	else if(xx1 == 6){ai = 3; aj = 3;}

	if(xx2 == 1){bi = 4; bj = 4;}
	else if(xx2 == 2){bi = 4; bj = 3;}
	else if(xx2 == 3){bi = 3; bj = 4;}
	else if(xx2 == 4){bi = 4; bj = 2;}
	else if(xx2 == 5){bi = 2; bj = 4;}
	else if(xx2 == 6){bi = 3; bj = 3;}
}

function marka()
{
	var xx1 = document.first.amat.value;
	var xx2 = document.first.bmat.value;
	
	seta(xx1,xx2);

	for(var a=1; a<4; a++)
	{
		for(var b=1; b<4; b++)
		{
			var sd = eval("document.first.a"+a+b);
				sd.removeAttribute("disabled");
				sd.value="";

			if(a >= ai || b >= aj)
			{
				sd.setAttribute("disabled","true");
				sd.value = "0";
			}
		}
	}

	for(var a=1; a<4; a++)
	{
		for(var b=1; b<4; b++)
		{
			var sd = eval("document.first.b"+a+b);
				sd.removeAttribute("disabled");
				sd.value="";

			if(a >= bi || b >= bj){
				sd.setAttribute("disabled","true");
				sd.value= "0";}
		}
	}

	for(var a=1; a<4; a++)
	{
		for(var b=1; b<4; b++)
		{
			var sd = eval("document.first.aa"+a+b);
			sd.removeAttribute("disabled");
			sd.value="";

			if(a >= ai || b >= bj)
				sd.setAttribute("disabled","true");
		}
	}

	for(var a=1; a<4; a++)
	{
		for(var b=1; b<4; b++)
		{
			var sd = eval("document.first.ba"+a+b);
			sd.removeAttribute("disabled");
			sd.value="";

			if(a >= ai || b >= bj)
				sd.setAttribute("disabled","true");
		}
	}
}

function madd()
{
	var xx1 = document.first.amat.value;
	var xx2 = document.first.bmat.value;
	seta(xx1,xx2);

	if(aj != bi)
	{
		alert("We can multiply two matrix only when the number of columns of first matrix is equal to number of rows of second matrix.");
	}
	else{
		var a11 = document.first.a11.value;
		var a12 = document.first.a12.value;
		var a13 = document.first.a13.value;
		var a21 = document.first.a21.value;
		var a22 = document.first.a22.value;
		var a23 = document.first.a23.value;
		var a31 = document.first.a31.value;
		var a32 = document.first.a32.value;
		var a33 = document.first.a33.value;

		var b11 = document.first.b11.value;
		var b12 = document.first.b12.value;
		var b13 = document.first.b13.value;
		var b21 = document.first.b21.value;
		var b22 = document.first.b22.value;
		var b23 = document.first.b23.value;
		var b31 = document.first.b31.value;
		var b32 = document.first.b32.value;
		var b33 = document.first.b33.value;

	
		var ssd = false;
		for(var a=1; a<4; a++)
		{
			for(var b=1; b<4; b++)
			{
				if(a < ai && b < bi){
					var axx = eval("a"+a+b);
					//alert("a"+a+b+"="+axx+" - - "+ai);
					if(axx == "")
						ssd = true;
				}
				if(a != aj && b != bj){
					var bxx = eval("b"+a+b);
					if(bxx == "")
						ssd = true;
				}
			}
		}

		if(ssd==true){
			alert("Empty cells are present. Please fill proper values");
		}
		else
		{
			aa11 = "("+a11+"*"+b11+")+("+a12+"*"+b21+")+("+a13+"*"+b31+")";
			aa12 = "("+a11+"*"+b12+")+("+a12+"*"+b22+")+("+a13+"*"+b32+")";
			aa13 = "("+a11+"*"+b13+")+("+a12+"*"+b23+")+("+a13+"*"+b33+")";
			aa21 = "("+a21+"*"+b11+")+("+a22+"*"+b21+")+("+a23+"*"+b31+")";
			aa22 = "("+a21+"*"+b12+")+("+a22+"*"+b22+")+("+a23+"*"+b32+")";
			aa23 = "("+a21+"*"+b13+")+("+a22+"*"+b23+")+("+a23+"*"+b33+")";
			aa31 = "("+a31+"*"+b11+")+("+a32+"*"+b21+")+("+a33+"*"+b31+")";
			aa32 = "("+a31+"*"+b12+")+("+a32+"*"+b22+")+("+a33+"*"+b32+")";
			aa33 = "("+a31+"*"+b13+")+("+a32+"*"+b23+")+("+a33+"*"+b33+")";
	

			document.first.aa11.value = aa11;
			document.first.aa12.value = aa12;
			document.first.aa13.value = aa13;
			document.first.aa21.value = aa21;
			document.first.aa22.value = aa22;
			document.first.aa23.value = aa23;
			document.first.aa31.value = aa31;
			document.first.aa32.value = aa32;
			document.first.aa33.value = aa33;

			for(var a=1; a<4; a++)
			{
				for(var b=1; b<4; b++)
				{
					if(a < ai && b < bj){

					}
					else
					{
						var dfx = eval("document.first.aa"+a+b);
						dfx.value="";						
					}
				}
			}


			for(var a=1; a<4; a++)
			{
				for(var b=1; b<4; b++)
				{
					if(a < ai && b < bj){
						//alert(a+"-"+b+"-"+ai+"-"+bj);
						var axx = eval("aa"+a+b);
						var dfx = eval("document.first.ba"+a+b);
						dfx.value=eval(axx);
					}
					else
					{
						var dfx = eval("document.first.ba"+a+b);
						dfx.value="";						
					}
				}
			}
	
		//-----------------------//
		}
	}
}


function color(test)
{
var cn =document.getElementsByTagName("input");
cn = cn.length;

	for(var j=19; j<37; j++)
	{
			var myI=document.getElementsByTagName("input").item(j);
			//myI.setAttribute("style",ch);
			myI.style.backgroundColor=test;
	}
}


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