<!-- Javascript .js file for Two Resistors in Parallel Equation --><!-- Javascript code for calculating Requiv. of two resistors in parallel -->

function RSolve(form) {
	var R1=0; R2=0; Req=0;// Initialize R1, R2 to high R
	R1=eval(form.R1.value);
	R2=eval(form.R2.value);
	Req=eval(form.Req.value);
	
if (R1<0 || R2<0 || Req<0)
	alert ("R value ERROR - Invalid entry. Positive values only");
		
	else{
	if (R1>0 && R2>0) 
		{
		Rt=R1*R2/(R1+R2); // Product Sum Rule for 2 resistors
		Req_rnd = Math.round(100*Rt)/100; // Round to hundredths
		Req = Req_rnd;
		form.Req.value = Req; // Put result into form
		}
		else if (Req>R1) {
				alert("R1 must be greater than Req"); 
		}
			 
		else if (Req>R2) {
				alert("R2 must be greater than Req"); 
		}
		
		else if (R1>0 && Req>0) {
				R2=R1*Req/(R1-Req); // Product Diff Rule for 2 resistors
				R2_rnd = Math.round(100*R2)/100; // Round to hundredths
				R2 = R2_rnd;
				form.R2.value = R2; // Put result into form
		}
		
		else if (R2>0 && Req>0){
				R1=R2*Req/(R2-Req); // Product Diff Rule for 2 resistors
				R1_rnd = Math.round(100*R1)/100; // Round to hundredths
				R1 = R1_rnd;
				form.R1.value = R1; // Put result into form
		}
		else
				alert("Something is weird in your R values!");
	}
}