如何从 addeventlistener 中断或返回

Question

I don't know how to break or return from addEventListener

Here I get "Undefined label 'testfunc'" error

testfunc:
    test.addEventListener("click", function(){
        console.log("TEST")
        break testfunc
    })

Here I get "TEST" everytime i click but I want it only to console.log("TEST") only once

function testfunc(){
    test.addEventListener("click", function(){
        console.log("TEST")
        return
    })
}

Answer 1

You cannot return testfunc from an event in your listener since your listener anonymous function will be executed on click event, after testfunc is executed.

What you can is prevent your event listener anonymous function to be reexecuted . To do so, write a condition with a variable which will be set to true after it is executed once.

 let isClicked = false; function testFunc(){ document.addEventListener("click", function(){ if (isClicked) return; // Will be executed once. console.log("TEST"); isClicked = true; }) } testFunc();

Answer 2

you can create some variable and put there flag (true/false), for example:

 let isClicked = false; function testfunc(){ test.addEventListener("click", function(){ if (isClicked) return; console.log("TEST") isClicked = true }) }