JAVASCRIPT COMPREHENSIVE EXAM 2026.pdf

JAVASCRIPT COMPREHENSIVE EXAM 2026/2027
QUESTIONS AND SOLUTIONS RATED A+
✔✔clearInterval - ✔✔cancels a timed, repeating action which was previously
established by a call to setInterval().

✔✔intervalId - ✔✔let intervalID = setInterval(function() { console.log("Happening every
500ms!"); }, 500);

clearInterval(intervalID);

✔✔Object LIteral - ✔✔A comma-separated list of name-value pairs wrapped in curly
braces.

var person = {firstName:"John", lastName:"Doe", age:50, eyeColor:"blue"};

✔✔document.querySelector() - ✔✔Returns the first Element within the document that
matches the specified selector, or group of selectors, or null if no matches are found.

✔✔document.querySelectorAll() - ✔✔Returns a list of the elements within the document
(using depth-first pre-order traversal of the document's nodes) that match the specified
group of selectors. The object returned is a NodeList.

✔✔.addEventListener - ✔✔('click' ( ) {
p.textContent = input.value
})

✔✔.textContent - ✔✔similar to .innerHTML

✔✔.innerHTML - ✔✔can read and alter the elements on a webpage

✔✔return - ✔✔ends function execution and specifies a value to be returned to the
function caller

✔✔ternary - ✔✔this.items = items !== undefined ? items : [];
(if items is undefined, return items; otherwise return the array)

✔✔<script>
var toys = ["jacks", "matchbox cars", "yo-yos", "marbles"];

// ES5
// for(var i = 0; i < toys.length; i++){
// console.log(toys[i]);
// }

, </script> - ✔✔for loop that prints all items in array

✔✔<script>
var toys = ["jacks", "matchbox cars", "yo-yos", "marbles"];

// ES6
// for(var toy of toys){
// console.log(toy);
// }

</script> - ✔✔for of loop that prints all items in array

✔✔<script>
var toys = ["jacks", "matchbox cars", "yo-yos", "marbles"];

// jQuery
// $.each(toys, function(index, value){
// console.log(value);
// });

</script> - ✔✔The $.each() function internally retrieves and uses the length property of
the passed collection.

✔✔button.addEventListener('click', () => {
p.innerHTML = input.value + ':';
}); - ✔✔When the button is clicked, the text between the <p> tags is changed per what
is typed into input box

✔✔What is a dataset? - ✔✔The dataset property on the HTMLElement interface
provides read/write access to all the custom data attributes (data-*) set on the element.
This access is available both in HTML and within the DOM. It is a map of DOMString,
one entry for each custom data attribute.

✔✔Math.floor() - ✔✔A function that returns the largest integer less than or equal to a
given number.

✔✔parseFloat() - ✔✔This function parses a string and returns a floating point number.

This function determines if the first character in the specified string is a number. If it is, it
parses the string until it reaches the end of the number, and returns the number as a
number, not as a string.

✔✔parseInt() - ✔✔This function parses a string and returns an integer. (Only the first
number gets returned.)