In the first case, when the user hits the "C" button we'd like to clear the display.
To determine what should we do, we'll use e.target.innerText, which will simply give back the label of the button that was clicked. (An advanced solution would be to only add event listener to the buttons container and use event bubbling but this is a more beginner-friendly solution.) To add event listeners for the buttons, we'll map through the buttons array and add a click event listener for each.
The next and last step we have to make is to add event listener to the buttons and build the functionalities. Then we have a div with the class of buttons which will represent the keypad of the calculator.Įnter fullscreen mode Exit fullscreen mode It is empty, because we will modify its content from Javascript. Inside our container we have an empty div with the id of display, and this will be the display of our calculator. We will use these wrappers to position our calculator on the page. In the body we have a section and inside that a div with a container class. This needs to be at the bottom, because this way, when our javascript runs, the html elements required for the calculator will be in the DOM. At the bottom of our body I included the index.js script that we will create later. We'll start out with a standard HTML5 boilerplate. The html will be pretty simple for this project. If you would watch a detailed step-by-step video instead you can check out the video I made covering this project on my Youtube Channel: In my opinion this is a really good beginner project for those who want to become web developers. You'll learn about event handling, and DOM manipulations throughout the project. The function will then access the text input object and replace whatever the current value is with the answer from the eval() function.In this tutorial we will create a fully working calculator using only HTML, CSS and vanilla Javascript.
#JAVASCRIPT CSS HTML CALCULATOR CODE CODE#
The eval() function treats the string as if it were JavaScript code and executes it and returns the results. This allows us to build our string with numbers and operators. If the user clicks on any other button, the function will access the text input object and append the value that was passed over to whatever is already in our text input. This will basically remove whatever string is already inside the text input. Once it is accessed, the value inside the text input is set to ” (2 single quotes) which is an empty string. If the user clicks on the C button or the clear button, it accesses the text input object, which represents our calculator screen, via the DOM. If(document.getElementById( ' valueshow ').value = ' 0 ')ĭocument.getElementById( ' valueshow ').value = buttonValue ĭocument.getElementById( ' valueshow ').value += buttonValue ĭocument.getElementById( ' valueshow ').value = answer Here is the JavaScript code for the 2 functions:ĭocument.getElementById( ' valueshow ').value = ' 0 ' .bgoperationcolor is use for all operation buttons (+,-,*,/) .bgcolornumber class is use for all button number buttons (0-9) It also control the left, top margin of calculator. div control the all calculator component like (buttons, text field ). The = button calls the calculate JavaScript function and passes the value that is in the text input which represents the string of numbers and operators that were pushed. Two types of inputs text and button are used here on a table within a form element and OnClick event was used to insert button values on the screen or to evaluate the numbers. All the buttons, except for the = button, will call the cal JavaScript when clicked and passes it’s associated value. Most of the HTML is coding for all the input buttons and their associated onclick event handlers. The following code is to make html calculator.
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