JavaScript Variables and Types Syntax Quiz

Which keyword is used to declare variables in JavaScript?

What method is used to find the largest value between two numbers in JavaScript?

Which of the following data types is not valid in JavaScript?

What is the result of '5 + 4 + (2 * 3)' in JavaScript?

What comment syntax is used in JavaScript similar to Java?

If a variable has not been declared and does not exist, what value does it hold in JavaScript?

What does document.getElementById return in JavaScript?

How can you change the text inside most elements in the DOM using JavaScript?

In JavaScript, what property can be set to change the text in form controls like textboxes?

What does the function changeText() in JavaScript do?

Which method allows you to manipulate or initialize text in JavaScript?

Which CSS style property is NOT changed in the function Preetify() in JavaScript?

What type of programming is JavaScript known for?

In JavaScript, what is used to write a JavaScript function that will run when an event occurs?

What is an example of an event attribute commonly used in HTML?

How can a JavaScript function be invoked in response to a user's click on an element?

What is a common drawback associated with using alert windows in JavaScript?

Which HTML attribute is used to set a JavaScript function as an event handler for element interactions?

In JavaScript, variables are declared using the var keyword.
Variable types are not specified, but JavaScript has types including Number, Boolean, String, Array, Object, Function, Null, and Undefined.
The typeof operator can be used to find out a variable's type.

Integers and real numbers are the same type in JavaScript.
Same operators are used for numbers: +, -, *, /, %, ++, --, =, +=, -=, *=, /=, %=.
Many operators auto-convert types, e.g., "2" * 3 is 6.

The Math object has methods: abs, ceil, cos, floor, log, max, min, pow, random, round, sin, sqrt, tan.
The Math object has properties: E and PI.
Examples: var rand1to10 = Math.floor(Math.random() * 10 + 1);, var three = Math.floor(Math.PI);.

Most JavaScript code manipulates elements on an HTML page.
We can examine elements' state and change state.
Examples: see whether a box is checked, insert new text into a div, change styles.

document.getElementById returns the DOM object for an element with a given id.
We can change the text inside most elements by setting the innerHTML property.
We can change the text in form controls by setting the value property.

A function is a block of code that can be called multiple times from different parts of the script.
Example: function changeText() { ... }.
Functions can be used as event handlers.