eventlistener runs without clicking [duplicate]

Question

document.getElementById("hit").addEventListener("click",console.log('test'))

I have that line of code, hit is an id of a button : <button id = "hit" value="Hit">Hit</button> Refreshing the page outputs "test" in the console and i dont know why.

Answer 1

When you pass parameters to a function it is immediately called. You need to pass a function that will wait for the event and then call console.log with the specified parameters.

document.getElementById("hit").addEventListener("click",() => console.log('test'))

Answer 2

addEventListener("click",console.log('test')) will immediately run console.log('test') and pass the return value of console.log. The return value will be undefined, so your code is equivalent to this:

document.getElementById("hit").addEventListener("click", undefined);
console.log('test');

OR

const consoleReturnValue = console.log('test'); // will be undefined
document.getElementById("hit").addEventListener("click", consoleReturnValue );

I assume that what you are you trying to achieve is

addEventListener("click", () => console.log('this'));

Or, if you can't use ES6:

addEventListener("click", console.log.bind(window, 'this'));

In this case you actually pass a function as the second argument instead of the undefined primitve.

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Fun fact, passing undefined as an argument is the same as not passing it, so your current addEventLinster call is the same as as:

document.getElementById("hit").addEventListener("click");
console.log('test');