I want to calculate two numbers and its pretty simple.

But Is there any way to take operator in variable and then do the calculation?

var x = 5;
var y = 5;
var p = '+';
var z = x + p + y;

$(".button").click(function() {
  alert(z);
});

<script src=".1.1/jquery.min.js"></script>
<div class="button">Click ME !</div>

I want to calculate two numbers and its pretty simple.

But Is there any way to take operator in variable and then do the calculation?

var x = 5;
var y = 5;
var p = '+';
var z = x + p + y;

$(".button").click(function() {
  alert(z);
});

<script src="https://ajax.googleapis./ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="button">Click ME !</div>

• javascript
• variables

Share Improve this question Follow edited Jul 4, 2015 at 18:23 Salman Arshad 273k8484 gold badges443443 silver badges534534 bronze badges asked Apr 14, 2015 at 8:08 TwixTwix 38744 silver badges1616 bronze badges 3

• 2 A simple switch...case would do. – Salman Arshad Commented Apr 14, 2015 at 8:11
• Here's answer to your question - stackoverflow./questions/5834318/… – Yellen Commented Apr 14, 2015 at 8:12
• 1 If you only need to decide between + and - you can also just multiply with var p = 1 or var p = -1. – Nils_M Commented Apr 14, 2015 at 10:05

Add a ment  | 

4 Answers 4

Sorted by: Reset to default 15

Avoid eval whenever possible. For this example, a simple switch...case statement will be sufficient:

var x = 5;
var y = 5;
var z;
var p = "+";
switch (p) {
    case "+":
        z = x + y;
        break;
    case "-":
        z = x - y;
        break;
}

---

You can also use a map of functions:

var fnlist = {
    "+": function(a, b) { return a + b; },
    "-": function(a, b) { return a - b; }
}
var x = 5;
var y = 5;
var p = "+";
var z = fnlist[p](x, y);

Or use parseInt on the string which you will be adding the variable to:

	var x = 5;
	var y = 5;
	var p = '-';
	var z = x + parseInt(p + y);

$(".button").click(function(){
  alert(z);
});

<script src="https://ajax.googleapis./ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="button">Click ME !</div>

You are looking for eval function:

	var x = 5;
	var y = 5;
	var p = '+';
	var z = x + p + y;

$(".button").click(function(){
  alert(eval(z));
});

<script src="https://ajax.googleapis./ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="button">Click ME !</div>

However, you have to remember that using eval function is potentially risky. For example, if used in the wrong way it can allow one to make injection attacks. Debugging can be also more difficult. I suggest to read this question.

you can use the eval function:

var x = 5;
var y = 5;
var p = '+';
var z = eval(x + p + y);

alert(z);