javascript - window.addEventListener('message', myFunction(event)) doesn't work -

i'm trying understand why following not work.

var myfunction = function(event) {     // event };  window.addeventlistener('message', myfunction(event));

i following error: "referenceerror: event not defined".

however, following works , event able used.

window.addeventlistener('message', function(event) {     // event });

how can use event in first situation? why event accessible in second situation?

you seeing error because invoking function immediately. need pass reference function instead.

in other words, change this:

window.addeventlistener('message', myfunction(event));

to this:

window.addeventlistener('message', myfunction);

when using addeventlistener() method, event object passed first parameter default when event fired.

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