How do I call a function with javascript variable

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I need to call a function in javascript, that function's name includes a variable (r):
Example
function funclk_r(){
do something
}
How can I arrange name of function '

funclk_

' then (r) then ()?

What I have tried:

<script>
    var r=48;
        function 'funclk_'+r(){
            alert("hi");
        }
    </script>

Not working!

Posted 5-Mar-23 11:30am

Member 14819235

Updated 5-Mar-23 22:36pm

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Nitin S · Answer 1 · 2023-03-05T19:24:00

Solution 1

You can use the eval function in javascript to execute js code as a string

var r=48;
function funclk_48(){
  alert("48");
}
function funclk_49(){
  alert("49");
}
function funclk_50(){
  alert("50");
}

eval("funclk_"+r+"()");

fiddle here - JSFiddle - Code Playground[^]

Posted 5-Mar-23 19:24pm

Nitin S

Comments

Member 14819235 17-Mar-23 18:23pm

Thnx

Richard Deeming · Answer 2 · 2023-03-05T22:36:00

Based on your question, you want to define and call global functions with a name defined at runtime.

To do that, you can use the indexer on the window object to get or set a global property with a constructed name:

JavaScript

const defineGlobalFunction = (r) => {
    window[`funclk_${r}`] = () => {
        alert(`Hi from function ${r}`);
    };
};

const callGlobalFunction = (r) => {
    const fn = window[`funclk_${r}`];
    if (typeof fn === "function") {
        fn();
    } else {
        console.error("Global function", r, "has not been defined");
    }
};

Demo[^]

NB: Whilst you could potentially use eval as suggested in solution 1, it can cause problems. See Never use eval()! - JavaScript | MDN[^] for details.