Design a Scientific Calculator Using Html and Javascript

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There are plenty of ways to do math on a desktop computer using a built-in calculator, but another way is to build one yourself using a simple HTML code. To create a calculator using HTML, learn some basics about HTML, then copy the necessary code into a text editor and save it with an HTML extension. You can then use your calculator by opening up the HTML document in your favorite browser. By doing all of this, not only will you be able to do math in a browser, but you can also learn some fundamentals about the art of coding!

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Learn what each html function is doing. The code you will use to create your calculator is made up of many pieces of syntax that work together to define different elements of a document. Click here for an explanation of how to familiarize yourself with this process, or read on to learn what each line of text is doing in the code you'll be using to make your calculator.
- html: This piece of syntax tells the rest of the document what language is being used in the code. In coding, a number of languages used to code, and <html> tells the rest of the document that it will be in - you guessed it! - html.^[1]
- head: Tells the document that everything beneath it is data about data, also known as "metadata". The <head> command is usually used to define stylistic elements of a document, such as titles, headings, and so on. Think of it as an umbrella under which the rest of the code is defined.^[2]
- title: This is where you will name the title of your document. This attribute is used to define what the title of the document will be when opened in an html browser.
- body bgcolor= "#": This attribute sets the color of the code's background and body. The number in this set of quotes that appears after # corresponds to a predetermined color.
- text= "": The word in this set of quotes sets the color of the text on the document.
- form name="": This attribute specifies the name of a form, which is used to build the structure of what comes after it based on what Javascript knows that form name to mean. For example, the form name we will be using is calculator, which will create a specific structure to the document.^[3]
- input type="": This is where the action happens. The "input type" attribute tells the document what sort of text the values in the rest of the brackets are. For example, they could be text, a password, a button (as it will be for a calculator), and so on.^[4]
- value="": This command tells the document what will be contained in the input type specified above. For a calculator, these show up as our numbers (1-9) and operations (+,-,*,/,=).^[5]
- onClick="": This syntax describes an event, which tells the document that something should occur when the button is clicked. For a calculator, we want the text that displays in each button to by understood as such. So, for the "6" button, we'll put document.calculator.ans.value+='6' between the quotes.^[6]
- br: this tag initiates a line break in the document, so that whatever comes after it will appear a line below whatever came before it.^[7]
- /form, /body, and /html: these commands tell the document that the corresponding commands that were initiated earlier in the document are now ending.^[8]

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Copy the code below. Highlight the text in the box below by holding down your cursor in the top-left corner of the box, and dragging it to the bottom-right corner of the box so that all of the text is blue. Then, press "Command+C" on a Mac or "Ctrl+C" on a PC to copy the code the clipboard.

                                <                html                >                <                head                >                <                title                >HTML Calculator</                title                >                </                head                >                <                body                bgcolor                =                "#000000"                text                =                "gold"                >                <                form                name                =                "calculator"                >                <                input                type                =                "button"                value                =                "1"                onClick                =                "document.calculator.ans.value+='1'"                >                <                input                type                =                "button"                value                =                "2"                onClick                =                "document.calculator.ans.value+='2'"                >                <                input                type                =                "button"                value                =                "3"                onClick                =                "document.calculator.ans.value+='3'"                ><                br                >                <                input                type                =                "button"                value                =                "4"                onClick                =                "document.calculator.ans.value+='4'"                >                <                input                type                =                "button"                value                =                "5"                onClick                =                "document.calculator.ans.value+='5'"                >                <                input                type                =                "button"                value                =                "6"                onClick                =                "document.calculator.ans.value+='6'"                >                <                input                type                =                "button"                value                =                "7"                onClick                =                "document.calculator.ans.value+='7'"                ><                br                >                <                input                type                =                "button"                value                =                "8"                onClick                =                "document.calculator.ans.value+='8'"                >                <                input                type                =                "button"                value                =                "9"                onClick                =                "document.calculator.ans.value+='9'"                >                <                input                type                =                "button"                value                =                "-"                onClick                =                "document.calculator.ans.value+='-'"                >                <                input                type                =                "button"                value                =                "+"                onClick                =                "document.calculator.ans.value+='+'"                ><                br                >                <                input                type                =                "button"                value                =                "*"                onClick                =                "document.calculator.ans.value+='*'"                >                <                input                type                =                "button"                value                =                "/"                onClick                =                "document.calculator.ans.value+='/'"                >                <                input                type                =                "button"                value                =                "0"                onClick                =                "document.calculator.ans.value+='0'"                >                <                input                type                =                "reset"                value                =                "Reset"                >                <                input                type                =                "button"                value                =                "="                onClick                =                "document.calculator.ans.value=eval(document.calculator.ans.value)"                >                <                br                >Solution is                <                input                type                =                "textfield"                name                =                "ans"                value                =                ""                >                </                form                >                </                body                >                </                html                >

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Open a text editing program on your computer. There are a number of programs you can use, but for convenience and quality, we recommend using TextEdit or Notepad..^[9] ^[10]
- On a Mac, click on the magnifying glass at the top-right corner of your screen to open Spotlight. Once there, type in TextEdit and click on the TextEdit program, which should now be highlighted in blue.
- On a PC, open the Start menu at the bottom-left corner of your screen. In the search bar, type Notepad and click on the Notepad application, which will appear in the results bar to the right
2
Paste the HTML code for a calculator into the document.
- On a Mac, click on the body of the document and press "Command+V". You will then need to click on "Format" at the top of your screen and click "Make Plain Text" after pasting the code.^[11]
- On a PC, click on the body of the document and press "Ctrl+V".
3

Save the file. To do this, click on the "File" button at the top-left hand of your window, and click on "Save As..." on a PC or "Save..." on a Mac in the menu that drops down.
4

Add an HTML extension to the file name. In the "Save As..." menu, type in your file name followed by ".html", and then click "Save". For example, if you wanted to call this file my first calculator, you would save the file as "MyFirstCalculator.html"

1

Find the file you just created. To do this, type in the name of your file on Spotlight or in the Start menu's search bar as described in the previous step. You do not need to type the "html" extension.
2

Click on your file to open it. Your default browser will open your calculator in a new webpage.
3

Click the buttons on the calculator to use it. The solutions to your equations will appear in the solutions bar.

Add New Question

Question

Do I need to be connected to the internet?

Usually, HTML will run in your browser, even without an internet connection.
Question

How can I get more space between the buttons?

If you are using HTML, you can add in the cells to add extra padding or the CSS code button.
Question

What do I do if this code is not working for me?

The code will certainly work. If it is not working for you, then there might be some errors in your code. Just copy and paste the above code and follow all the procedures, and it should work fine.
Question

After I modify the code, can I distribute it freely?

Yes. These are simple codes for educational purposes; no one owns the rights for these codes.
Question

How can I make the buttons larger?

You can make the button size bigger by using the CSS tag. For eg:.button { background-color: #4CAF50; border: none; color: white; padding: 15px 32px; text-align: center; font-size: 16px; margin: 4px 2px;}
Question

What does the reset button do?

Nothing, it just redoes your whole equation, basically erasing the information you had on there.
Question

Is there a way to make custom buttons on this script?

Definitely. You can use CSS styling or attach background images to the button. You can also use the HTML canvas tag with Javascript to create.
Question

Can I create a calculator in normal notepad?

Yes, but it won't be as good as if you use other coding languages, like HTML or Javascript.
Question

How do I make the buttons larger when making a calculator using HTML? How do I add CSS or JS tags?

To make the button larger, we use CSS tags. In the body, type and on a new line type . In between them, type: .classname { width: 50%; padding: 50px 50px; font-size: 30px; text-align: center; } change the padding, with and font-size to whatever you want. Then go to the buttons. Inside the tag for each button, type class="classname"
Question

What do I do if the buttons aren't working on the calculator?

If you copied the code, try doing it again. If you coded it, then check the input variables and the conditionals.