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A function in JavaScript allows our code to be more maintainable and reusable. In Javascript, a function is a way to organize your code to make it easier to create and reuse. All functions have a name, are passed zeros or more pieces of information, and almost always return a value. A function can also group statements together. An example of a function could be “distance = speed x time”, which we discussed in class. in JavaScript, you would code this function as:

let speed = 10

let time = 7

alert (speed * time);

with would return distance = 70.

To call a function is typically the name the function you want to call (invoke) followed by parenthesis. To pass a function arguments means where your function call contains some data that you pass into the function. To pass a function arguments is used to easily customize a function. Additionally, the return keyword allows you to send data back to whatever called your function to begin with. No code in your function after return will run. Once your function hits the return keyword, it stops everything and and returns whatever value you specified to the caller and exits the function. 

 

In JavaScript, a variable stores the data value that can be changed later on. To create a variable, use the “let” keyword followed by the name you want to give your variable. In JavaScript, you can either declare a variable or initialize one. The difference between these two terms is that when a variable is declared, the variable is registered using a given name within the corresponding scope (ex: inside a function). With initialization, when you declare a variable it is automatically initialized, which means memory is allocated for the variable by the JavaScript engine. There are a few rules / guidelines that come along when naming a variable in JavaScript which can include: your variable cannot start with a number, and spaces are not allowed. However, you can make your variables as long as you want and outside of the first character, your variable can include as many letters, numbers, and special characters as you want. The arithmetic operations in JavaScript include addition (+), subtraction (-), multiplication (*), division (/), and modulus (%). Addition adds two operands, subtraction subtracts the right operand with the left operand, multiplication multiplies two operands, division divides the right operand into the left operand with the result always being a floating-point number, and lastly, modulus divides the right operand into the left operand and returns the remainder. There are other arithmetic operations such as exponentiation, however the five arithmetic operations listed above are most commonly used in JavaScript. Concatenation is a very common task that allows you to combine separate strings together. Concatenation operators allow you to do this task and are coded as a + or +=. The + concatenation is used for concatenates two values, whereas the += adds the result of the expression to the end of the variable. The prompt () term lets you get input from the user. For example, you could use let myText = prompt(“Hello Earth”) to prompt the user with Hello Earth in a dialogue box. 

The coding language responsible for adding structure to a web page would be HTML which makes up the layout for your website. It is a dynamic language that allows you to create a starting point for your website with less code, and is what most static pages start from. The coding language responsible for adding functionality to a webpage would be JavaScript which is mainly designed to provide interactive web content. Everything in JavaScript starts by following an event. It can interact with HTML elements in the browser, and without JavaScript a webpage is inanimate. The coding language responsible for adding design elements to a webpage would be Cascading Style Sheets (CSS). It is used to add colors, layouts, and fonts to a website. 

We use loops in JavaScript to preform repeated tasks based on a given condition. They are crucial or saving time and minimizing errors. Typically, conditions will return true or false and a while loop will continue to run until the condition returns false. For loops will loop through a block of code a set number if times. Loops include three main parts starting with initialization where the loop variable is initialized and iterated through the loop. Next comes condition where the loop will only continue if the value it returns is true, otherwise it will exit. Last comes iteration where the updated value of the variable is iterated. 

Week 12

Why do we use loops?
-Loops are very convenient because it allows the programmer to shorten what could be hundreds of thousands of lines of code to just a few lines. It allows the programmer to write the code once and repeat it as many times needed.

To run it a specific number of times, use a “For” loop. If we don’t have a specific number of times, use a “While” loop.

A “For” loop code looks like — for (int i = 0; i < 10; I++)

 

Week 13

Which coding language adds structure to a web page?
-Use HTML. It makes up the layout and structure for a website,

Which coding language adds functionality to a web page?
-Use JavaScript. It is designed to provide interactivity on your webpage.

Which coding language adds design elements to a web page?
-Use CSS. It is used for adding colors, layouts, and fonts.

JavaScript is event driven because it allows its users to create something and then it processes to codes. For example when we were learning to write codes, it was up to us to write something in order for JavaScript to do something when we ran it. JavaScript teaches you to be able to create something of your own and it works to make sure your code is correct to run. 

CSS and HTML are things we only talked about very briefly in our last class, however the seem to be kind of important. HTML is about adding structure to your page. While, CSS is the design aspect, and makes your code look better. To my understanding, CSS stands for Cascading Style Sheets and its job is to take take the HTML elements and properly display them on our screen.

Loops are important to writing your JavaScript code because they allow you to repeat codes. Loops help with when you want to repeat a code, the loop makes it easier to shorthand a way to write the code simply. The goal of a loop is to write out instructions until a condition is completed. They are used to complete true or false responses. So, for multiple situations you may be needing to find out if something is true or false using slightly different data, you would use your loop to create the statement and then add your data to the one loop to find multiple answers. 

A for loop is used for when we have a specific number of times to run the code. The beginning part of the code that begins “for(){“, allows us to insert information on when the loop code should run and how many times it is needed. If we did not know how many times, we would use a while loop instead.