function checnum(as)
{
	var a = as.value;
	for(var x=0; x<a.length; x++)
	{
		var ff = a[x];
	
		if(isNaN(ff) && ff != "/" && ff != "-")
		{
			alert("Enter a proper value");
			break;
		}
	}
}

function slope()
{
	var a = document.first.a.value;
	var b = document.first.b.value;
	if(a==0 || b==0)
	{
		alert("Intercept cannot be zero");
	}else{
	var p = b + "x ";
	var q = a + "y ";
	var r = a*b;
	if(a>0)
		q="+ " + q;
	if(r>0)
		r="+ " + r;
	document.first.r1.value = p + q + r;
	}
}
	
function color(test)
{

	for(var j=2; j<10; 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;
}