How to pass the value of a variable instead of a reference into a function in Javascript

Question

If I use the code below, the alert will say 10 . I want it to say 5 .

var a = 5;
var b = document.getElementById("element").onclick = ()=>alert(a);
a = 10;

How can I create an event listener that uses the value of a variable from the time it was created, rather than a reference that will change if I modify value later?

Answer 1

Use an IIFE that captures the current value of a .

 var a = 5; document.getElementById("element").onclick = ((x) => ()=>alert(x))(a); a = 10;

 <button id="element">Click</button>