How to Sum Up User Input with JavaScript

Learn how to store user input in JavaScript and calculate the sum of values effortlessly. A beginner-friendly guide that walks you through the essential steps.
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How to Sum Up User Input with JavaScript: A Step-by-Step Guide

Are you struggling to store user input in a variable and to sum those values using JavaScript? You're not alone! Many developers, both novice and advanced, encounter this scenario. In this post, we'll break down the process of capturing user input, storing it effectively, and calculating the sum of those inputs step-by-step.

The Problem

You want to create a simple interface where users can input prices of different products, and you would like to add them up. While you have a basic structure in place, you might be stuck on how to accumulate these values over time and output them correctly. Fear not! We’ll guide you through each part of the solution.

Understanding Your Code

Before jumping into the solution, let's examine your current code structure:

[[See Video to Reveal this Text or Code Snippet]]

[[See Video to Reveal this Text or Code Snippet]]

In your existing code:

You retrieve the value from an input field where prices are entered.

You attempt to store that value and push it into an array called sum.

However, as you mentioned in the edit, you want to add each subsequent value to the existing sum.

The Solution

Let’s enhance your code by adding a function to calculate the total sum of all inputs. Here's how to do it:

Step 1: Gather User Input

You will continue using getElementById to get your user input for prices.

Step 2: Store Inputs in an Array

Instead of creating a new array each time, you need to ensure that your array exists at a global scope to accumulate inputs every time a price is entered.

Step 3: Calculate the Sum

We'll define a function that will sum all elements in your array.

The Updated Code

Here's the complete solution incorporating all of the steps:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code

HTML Structure: We added a button to submit the input.

Input Handling: We attach an event listener to the button, triggering the function that adds the price to our sum array.

Sum Calculation: The getSumOfArray function iterates through the array and returns the total sum.

Summary

In just a few steps, you can effectively store user input in JavaScript, keep a running total of prices, and output the calculated sum whenever needed. By using an array to hold the values and a simple iteration function to sum them up, you've created a functional price tracker!

Feel free to experiment with this code and modify it for your own projects. Happy coding!