dom-events Flashcards

1
Q

Why do we log things to the console?

A

We log things to the console so we know/can see what is going on in our Javascript.

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2
Q

What is the purpose of events and event handling?

A

An event handler is a routine that deals with the event, allowing a programmer to write code that is executed when the event occurs.

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3
Q

Are all possible parameters required to use a JavaScript method or function?

A

No, all possible parameters required to use a JavaScript are not just a method or a function.

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4
Q

What method of element objects lets you set up a function to be called when a specific type of event occurs?

A

The addEventListener() method of the EventTarget interface sets up a function that will be called whenever the specified event is delivered to the target. Common targets are Element , or its children, Document , and Window , but the target may be any object that supports events.

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5
Q

What is a callback function?

A

A callback function is a function passed into another function as an argument, which is then invoked inside the outer function to complete some kind of routine or action.

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6
Q

What object is passed into an event listener callback when the event fires?

A

The function that we assign as a callback to an event listener is passed the event object as its first argument. We can use this object to access a wealth of information about the event that has occurred: type (string) This is the name of the event. target (node) This is the DOM node where the event originated.

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7
Q

What is the event.target? If you weren’t sure, how would you check? Where could you get more information about it?

A

The read-only target property of the Event interface is a reference to the object onto which the event was dispatched. It is different from Event.currentTarget when the event handler is called during the bubbling or capturing phase of the event.

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8
Q

What is the difference between these two snippets of code:

element. addEventListener(‘click’, handleClick)
element. addEventListener(‘click’, handleClick())

A

The parentheses are omitted where the function is called because they would indicate that the function should run as the page loads (rather than when the event fires).

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