Build Identical Calicutor App Like Mac Using Jquery Rating: 9,7/10 7140 reviews

Mar 15, 2017  JQWidgets is a jQuery-powered framework created to empower developers to build responsive, fast, and robust UI components for websites. JQWidget’s components have been created to leverage jQuery. This is the second post in the “Using jQuery in ASP.NET applications” series where we tackle the how you can access your code base with a jQuery ajax call. Setting up the project. Open up Visual Studio and create a new ASP.NET MVC 3 Web Application Enter a name and a location and click the OK button.

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There are two ways to use jQuery, either downloaded locally or on a Content Delivery Network (CDN). The local copy is just that, a file that sits within your document root on your server’s hard drive. A CDN-hosted version means that the jQuery file sits on someone else’s server and you just reference it in your code.

Whether you use a local copy of a CDN is up to you. For production websites, use a local copy of jQuery for speed and reliability. However, in development, it’s okay to use the CDN version of jQuery.

Install jQuery locally

jQuery is available as a download. Once there, select the Production version and click Download. Depending on your browser’s settings you may end up with a page full of JavaScript code. If that’s the case, select Save As from the File menu.

In other cases, you’ll simply be prompted to download a file. In the end, you want to end up with a file named like jquery-1.8.1.min.js, regardless of whether you save the file or download it.

The file should be placed into your document root. Remember the filename; you’ll need it later.

That’s all there is to installing jQuery — download it and put the file into your document root.

Use CDN-hosted jQuery

The CDN-hosted option for jQuery is great for development. You don’t have to worry about downloading the file or putting it in the right place; it’s always available (as long as the CDN is up). CDN-hosted versions are available from many of the big-time players on the web, like Google and Microsoft.

You don’t need to download anything in order to use a CDN-hosted jQuery, so this section is short and sweet. You can find the links for the CDN-hosted versions at

Previously, I showed you how to use CSS border-radius property to create the following calculator. Now I will show you how to use jQuery to implement the functionality of the calculator.

Adding jQuery

We will be using jQuery in this project to respond to events when a user clicks on a button. We need to add the jQuery library to our application. I will use the cdnjs CDN library to add jQuery.

At the bottom of my index.html file, I will add the following script tag:

Handling operator vs number buttons

Before writing my code, I decided to brainstorm how I would handle the functionality behind the calculator. I divide the buttons on the calculator into two groups: operator and number.

A number button would correspond to the numbers 0–9. All other buttons are operators.

Global variables for our operation

The next step is to determine how may global variables we will need. The global variables will hold the functionality of our calculator. For example, a user can enter the following sequence:

Likewise, a user can enter this much longer sequence:

When considering global variables initially, we might consider creating a new variable every time the user presses a key. This would not be very efficient. We would have to keep track of who knows how many variables as the user presses keys.

To improve on this, we can simplify things to only need four global variables:

  • num1
  • num2
  • operator
  • total

Let me show you how this works. The first number the user presses is stored in variable num1. The operator (i.e. +, — , *, / or enter) is stored in the operator. The next number entered is stored in variable 2. Once the second operator is entered, the total is calculated. The total is stored in the variable total.

A logical question would be what do you do with the third or fourth number that a user enters? The simple answer is that we reuse num1 and num2.

Once the total has been calculated, we can replace the value in num1 with the total. We would then need to empty out the operator and num2 variables. Let’s walk through this with our second example from above:

Now you see that we can handle every possible combination of buttons pressed by the user by using these 4 variables.

Getting the key the user pressed

Now that we have walked through our logic, we need to start the process of handling the key the user pressed. At the bottom of my index.html file, I will create a script tag that will hold my code.

The first step is to get the key that a user pressed. Here is a snippet of my index.html file that shows all the buttons on one row of the calculator:

Every button, whether it is a number or an operator, is defined using a <button><;/button> element. We can use this to catch when a user clicks on a button.

In jQuery, you can have a button click function. When a button is clicked, the function is passed an event object. The will contain the button that was clicked. I can get the value of the button by using the innerHTML property.

Here is the code that will console.log the button that a user clicks.

Now if you test the code, you will see the value of the key that you press. This works for every button in the calculator.

Creating our global variables

Now that we have the ability to determine what key was pressed, we need to start storing them in our global variables. I am going to create my four global variables:

Handling button when clicked

When a user clicks a button, they will be clicking on a number or an operator. For that reason I am going to create two functions:

In my button click function earlier, I can replace the console.log with a call to the appropriate function. To determine whether a button or operator was clicked, I can compare to see if it is between 0 and 9. If it is, the user clicked a number. If not, the user clicked an operator.

Here is my initial step to test to make sure I can tell which button was clicked:

Once I am satisfied that I am identifying each button clicked, I can replace the console.log with a call to the appropriate function:

Handling number buttons

When a user presses a number, it will be assigned to either num1 or num2 variable. num1 is assigned value of '. We can use this to determine what variable to assign the number. If num1 is empty then we assign the number to it. Otherwise, we assign it to num2.

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Here is what my handleNumber function looks like:

Handling operator buttons

Our function to handle when an operator button is pressed is very simple. All we need to do is to assign the value to our operator variable.

Here is what my handleOperator function looks like:

Displaying Buttons

The next step is to actually display the button pressed to the user. If you check out the functionality of the calculator on your phone, you will notice it only displays numbers. If a user presses the + key, it is not displayed.

In our index.html file, we have a div with a class of 'calc-result-input' that displays our input. We will use this to display numbers to our users.

Since we have separated out our calculator activity into functions, we will create a function to display the button.

Here is what my displayButton function looks like:

Since we only update the display when the user presses a number, we can call the displayButton function from within the handleNumber function.

Here is what my handleNumber function looks like now:

Handling totals

The next step is to calculate a total. A total is only calculated after a user presses an operator after having a value assigned to num1 and num2.

For example, if the user enters:

We want to sum num1 and num2 and display the total. Multi split screen software samsung mac.

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If the user enters:

We want to subtract num2 from num1 and display the total.

We create a handleTotal function to handle this. This function will create a total based on the operator pressed. Since there are multiple operators that can be pressed, we will use a case statement to handle them.

For simplicity’s sake, I am only going to show the code to handle when the user clicks the + operator button.

Here is the handleTotal function:

Converting String to Number for calculation

When we get the innerHTML of the button that is pressed, we get a string value. To sum two variables, they need to be converted to a number. There is a shorthand notation in JavaScript that will convert a string to a number by prefixing the variable with a + sign. You can see where I am doing this conversion on this line:

No access to apps mac free. Not to disparage Jim's suggestion, but I doubt Access will be produced for the Mac regardless of demand or how nicely you ask:-) Access is heavily dependent on ActiveX Controls which is a Windows-only technology.

When to call handleTotal function

Now that we have a function to calculate the total, we need to call it at the appropriate time. We only calculate total after a user enters their second operator.

To handle this we will need to make a change to our existing handleOperator function. Previously, we were assigning the operator variable the value of the operator button the user clicked. Now we need to know if this is the first operator the user has clicked or not. We don’t calculate a total when the user clicks on the first operator.

To account for this, we can check to see if the operator variable has a value of '. If so, this is the first operator. If operator has a value, then we will want to calculate a total.

Here is what the handleOperator() function looks like now:

Moving Script to app.js file

Currently our HTML and JavaScript code are all contained in the index.html file. We want to split out the logic into a separate file. I create a new file called app.js.

I copy the entire contents of the <script> tag into this file. I delete the opening &lt;script> tag and closing </script> tag in my index.html file.

Build Identical Calicutor App Like Mac Using Jquery

The last thing we need to do is to tell our index.html file where our scripts are. We do this by adding this line below the <script> tag that loads jQuery at the bottom of the index.html file:

Final Files

I now have these three files:

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  • index.html
  • app.js
  • style.css

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The index.html file is used to display the calculator to the user on the web page.

The style.css is used to style my calculator. Please review my previous article that talks about using the CSS border-radius property to style the calculator.

The app.js file contains the logic behind the calculator.

Here is what my app.js file looks like:


Our calculator works, but only if the user clicks the + operator. You can add to the functionality in the handleTotal function to account for all operators. I have all the functionality in my repo which you can find here.

Further Readings

Build Identical Calculator App Like Mac Using Jquery File

Breadth First Search in JavaScript — The two most common methods of searching a graph or a tree are depth first search and breadth first search. This story shows you how to use a breadth first search of a graph or a tree.

Instantiation Patterns in JavaScript — Instantiation patterns are ways to create something in JavaScript. JavaScript provides four different methods to create objects. Learn how to create all four in this article.

Using Node.js & Express.js to save data to MongoDB Database — The MEAN stack is used to describe development using MongoDB, Express.js, Angular.jS and Node.js. In this tutorial I will show you how to use Express.js, Node.js and MongoDB.js. We will be creating a very simple Node application, that will allow users to input data that they want to store in a MongoDB database.