Writing a code in javascript with radio buttons and using if else loop to calculate simple and/or compound interest

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I have been asked to write a code in javascript to show the results in the output boxes based on the input data.
I have written down the following code. However regardless of which radio buttons (Simple Interest or Compound Interest) I select, the program always calculates compound interest and displays the results accordingly. Where am I going wrong, could someone please advise. Thanks in advance.

What I have tried:

HTML

function calc() {

		var p = document.getElementById("p").value;

		var r = document.getElementById("r").value;

		var t = document.getElementById("t").value;

		var int = document.getElementById.value;

		

		if (int == "si") {

		var sip = (p \* r \* t) / 100

		var ta = p + sip

		document.getElementById("i").value = sip;

		document.getElementById("a").value = ta;

		} else	{

		var cta = p\*(Math.pow((1+r/100),t))

		var cmp = cta-p

		document.getElementById("i").value = cmp;

		document.getElementById("a").value = cta;			

		}

		}








	

	<h1> Interest Calculator </h1>

	Principal = 

	<br><br><br>

	Rate of Interest = 

	<br><br><br>

	Time (in years) = 

	<br><br>

	<h1> Interest Type </h1>

	 Simple Interest

	\  \  \  

	 Compound Interest

	<br><br>

	<hr noshade="">

	Interest 

	<br><br>

	Amount 

	<br><br>

	

	\ \ \

Posted 28-Apr-19 1:14am

Maloy Nandi

Updated 28-Apr-19 21:24pm

Patrice T

v2

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2 solutions

Solution 2

Resolved - see the revised code below

<!DOCTYPE html>
<html>
<head>
	<script>
		function calc() {
			p = document.getElementById("p").value;
			r = document.getElementById("r").value;
			t = document.getElementById("t").value;
			var int = document.getElementsByName("int").value;
			
			if (document.f.int[0].checked == true) {
			sip = (p * r * t) / 100;
			ta = (p*1 + sip*1);
			document.getElementById("i").value = sip;
			document.getElementById("a").value = ta;
			}
			
			else if (document.f.int[1].checked == true) {
			cta = p*(Math.pow((1+r/100),t));
			cmp = (cta*1-p*1);
			document.getElementById("i").value = cmp;
			document.getElementById("a").value = cta;			
			}
			}
	
	</script>
	
</head>
	<body>
		<form name = "f">
		<h1> Interest Calculator </h1>
		Principal = <input type = "text" id = "p" autofocus>
		<br><br><br>
		Rate of Interest = <input type = "text" id = "r">
		<br><br><br>
		Time (in years) = <input type = "text" id = "t">
		<br><br>
		<h1> Interest Type </h1>
		<input type = "radio" name = "int" value = "si"> Simple Interest
		      
		<input type = "radio" name = "int" value = "ci"> Compound Interest
		<br><br>
		<hr noshade>
		Interest <input type = "text" id = "i">
		<br><br>
		Amount <input type = "text" id = "a">
		<br><br>
		<input type = "button" name = "cal" value = "Calculate" onclick = "calc()">
		   
		<input type = "reset" value = "Reset">
		</form>	
	</body>
	
</html>

Posted 28-Apr-19 21:24pm

Maloy Nandi

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phil.o · Accepted Answer · 2019-04-28T01:25:00

Solution 1

JavaScript

var int = document.getElementById.value;

Something is missing on this line, between Id and .value.

Posted 28-Apr-19 1:25am

phil.o