Using bounce animation on a scaled element

What is the best way to have something scale and then perform a bounce animation at that scale factor before going back to the original scale factor. I realize I could do something like scaling it to 2.2, then 1.8, then 2.0, but I'm looking for a way where you just have to perform the bounce animation on the scale factor because my scale factor will change. Here is my example. Basically I want to combine the two to work like I said but as you can see the bounce animation performs based off the div size prior to scaling. P.S I want this done in one action, the two buttons were just for the example.

What is the best way to have something scale and then perform a bounce animation at that scale factor before going back to the original scale factor. I realize I could do something like scaling it to 2.2, then 1.8, then 2.0, but I'm looking for a way where you just have to perform the bounce animation on the scale factor because my scale factor will change. Here is my example. Basically I want to combine the two to work like I said but as you can see the bounce animation performs based off the div size prior to scaling. P.S I want this done in one action, the two buttons were just for the example.

function myFunction() {
            var image = document.getElementById('test');
            image.style.WebkitTransform = ('scale(2,2)');
        }
    function myFunction2() {
        var image = document.getElementById('test');
        image.classList.remove('bounce');
        image.offsetWidth = image.offsetWidth;
        image.classList.add('bounce') ;
    }


div#test  {
position:relative;
display: block;
width: 50px;
height: 50px;
background-color: blue;
margin: 50px auto;
transition-duration: 1s;

}
        
.bounce {
    animation: bounce 450ms;
    animation-timing-function: linear;
}

@keyframes bounce{
25%{transform: scale(1.15);}
50%{transform: scale(0.9);}
75%{transform: scale(1.1);}
100%{transform: scale(1.0);}
}


<div id='test'> </div>

<button class = 'butt' onclick = 'myFunction()'>FIRST</button>
<button class = 'butt' onclick = 'myFunction2()'>SECOND</button>


Render HTML with Vanilla JavaScript and lit-html

Render HTML with Vanilla JavaScript and lit-html

Sometimes you need to render HTML elements on a web page. And like Goldilocks' search for "just right", you have to try a few techniques before you find the right one. Using a framework may be too hard. Using pure HTML and the DOM API may be too soft. What you need is something in the middle that is just right. Is lit-html "just right"? Let's find out.

Sometimes you need to render HTML elements on a web page. And like Goldilocks' search for "just right", you have to try a few techniques before you find the right one. Using a framework may be too hard. Using pure HTML and the DOM API may be too soft. What you need is something in the middle that is just right. Is lit-html "just right"? Let's find out.

First, I'll show how this all works. Then at the end of this article, I'll explain everything you need to get started with lit-html to try this for yourself.

When you're done, you can push your HTML app with lit-html to the cloud to see it in all of its glory! I included a link to a free Azure trial, so you can try it yourself.

Resources:

The Sample App

Here is the app I'll demonstrate in this article. It fetches a list of heroes and renders them when you click the button. It also renders a progress indicator while it is fetching.

What's the Value of lit-html

When you focus on rendering content, and nothing else, lit-html is a good fit. It works closely with the DOM to render content, and refresh it in an optimal manner. The docs can provide you with more details, but the basic code for lit-html looks like this.

// Credit: As seen in official docs https://lit-html.polymer-project.org/guide/getting-started

// Import lit-html
import { html, render } from 'lit-html';

// Define a template
const myTemplate = name =>
  html`
    <p>Hello ${name}</p>
  `;

// Render the template to the document
render(myTemplate('World'), document.body);

You import lit-html, define a template, then render it to the DOM. That's it!

Rendering HTML

A progress bar is fairly basic. There is some HTML, and we show it when needed and hide it when it is not required. While we could use a template, or innerHTML, or the DOM API for this, let's see what this would look like with lit-html.

First, we get a reference to the element in the DOM where the progress bar will appear.

Then we define the template. This code looks and feels like JSX (or TSX). The advantage here is that you can write the HTML. You wrap the HTML in a template string (notice the back-tick character is used and not a single quote). Template strings allow you to span lines and insert variables where needed (we'll see this soon). The magic that makes this work is the html tag that precedes the template string. The html tag is what tells lit-html that you are about to define a template.

Next, we compile the template and pass those results to lit-html's render function, which places the results in the DOM. Finally, we hide or show the progress bar as needed.

function showProgress(show = true) {
  const container = document.getElementById('progress-placeholder');

  const template: () => TemplateResult = () => html`
    <progress class="progress is-medium is-info" max="100"></progress>
  `;
  const result = template();
  render(result, container);

  container.style.display = show ? 'block' : 'none';
}

Now you can run this showProgress function any time you want to show the progress bar.

Note that when a template is re-rendered, the only part that is updated is the data that changed. If no data changed, nothing is updated.

Rendering HTML with Dynamic Values

The progress bar does not change each time it is rendered. You will have situations where you want your HTML to change. For example, you may have a message area on your web app that shows a styled message box with a title and a message. The title and message will change every time you show the message area. Now you have dynamic values.

The HTML is defined with a template string, so it is trivial to add a variable into it. Notice the code below adds a title and text into the template, using the ${data.title} and ${data.text} syntax, respectively.

Then the template is compiled and rendered were needed.

When this template is re-rendered, the only part that is updated is the data that changed. In this case, that's the title and text.

function showMessage(text: string, title = 'Info') {
  const template: (data: any) => TemplateResult = (data: Message) => html`
    <div id="message-box" class="message is-info">
      <h3 class="message-header">${data.title}</h3>
      <p class="message-body">${data.text}</p>
    </div>
  `;

  const el = document.getElementById('message-placeholder');
  const result = template({ title, text });
  render(result, el);

  el.style.visibility = !!text ? 'visible' : 'hidden';
}

Rendering a List

Things get a little more real when we render a list. Let's think about that for a moment. A list requires that we have a plan if there is data and a backup plan if there is no data. A list requires that we render the same thing for each row, and we don't know how many rows we have. A list requires that we pass different values for each row, too. Then we have to take the rows and wrap them in a container such as a <ul> or a <table>.

So there is a little more logic here, regardless of whether we use lit-html or any other technique. Let's explore how the replaceHeroList function renders the rows using lit-html.

function replaceHeroList(heroes?: Hero[]) {
 const heroPlaceholder = document.querySelector('.hero-list');

 // Define the template
 let template: () => TemplateResult;

 if (heroes && heroes.length) {
   // Create the template for every hero row
   template = createList();
 } else {
   // Create the template with a simple "not found" message
   template = () =>
     html`
       <p>heroes not found</p>
     `;
 }

 // Compile the template
 const result = template();

 // Render the template
 render(result, heroPlaceholder);

Notice that when there are heroes, we call the createList function. This function begins by creating an array of TemplateResult. So for every hero in the heroes array, we define a template that represents the <li> containing the HTML that displays that respective hero.

Then we create another template that contains the <ul> and embeds the array of hero templates. It's pretty cool that we can embed templates like this! Finally, we return it all and let the logic compile the templates and render them.

function createList() {
  // Create an array of the templates for each hero
  const templates: TemplateResult[] = heroes.map(hero => {
    return html`
      <li>
        <div class="card">
          <div class="card-content">
            <div class="content">
              <div class="name">${hero.name}</div>
              <div class="description">${hero.description}</div>
            </div>
          </div>
        </div>
      </li>
    `;
  });

  // Create a template that includes the hero templates
  const ulTemplate: () => TemplateResult = () =>
    html`
      <ul>
        ${templates}
      </ul>
    `;
  return ulTemplate;
}

Summary

When you want to render HTML, lit-html is a fast and light-weight option. Is it better than using templates and the DOM API? You'll have to decide what is best for you. But the real story here is that you have another great option to consider when determining the right tool for your job.

Prologue

You can also get editor help with your lit-html templates. Notice the image below shows the syntax highlighting for the HTML template!

Setup

You can install the lit-html package with npm.

npm install lit-html

Alternately you can load it directly from the unpkg.com CDN

import { html, render } from 'https://unpkg.com/lit-html?module';

You have a choice here. npm is my preference, but feel 100% free to use the CDN if that suits you.

TypeScript and lit-html

You only need to include the library for lit-html and you're done. But I like to use TypeScript, and I absolutely recommend enabling your tooling to work great with typeScript and lit-html.

Let me be very clear here - you do not need TypeScript. I choose to use it because it helps identify mistakes while I write code. If you don't want TypeScript, you can opt to use plain JavaScript.

Here are the steps to make TypeScript and lit-html light up together:

  1. Install TypeScript support for lit-html
  2. Configure your tsconfig.json file
  3. Install the VS Code extension for lit-html

Run this command to install the plugin and typescript, as development dependencies to your project.

npm install --save-dev typescript-lit-html-plugin typescript

Edit your tsconfig.json by adding the following to your compilerOptions section.

"compilerOptions": {
  "plugins": [
    {
      "name": "typescript-lit-html-plugin"
    }
  ]
}

Finally, install the VS Code extension for lit-html.

Now you get syntax highlighting for all of your lit-html templates!

Get value from Javascript to HTML in Laravel

I want to ask that how can I call a value from javascript to html blade in laravel.

I want to ask that how can I call a value from javascript to html blade in laravel.

Here is my JavaScript code:

<script type="text/javascript">
    function valueFunction(){
        var output = document.getElementById('teacherId').value;
        console.log(output);
        document.getElementById('output').innerHTML = output;
    }
</script>

Here is my Laravel Html:

{{$users[]->name}}
<output id="output"></output>

As I am getting the value in output tag, but I want to call the value of javascrpt in {{$users[output]->name}} here.

Thank you.

Building a minesweeper game using Javascript, HTML and CSS

Building a minesweeper game using Javascript, HTML and CSS

In this article, you'll learn how to build minesweeper using JavaScript, HTML and CSS. I also used jQuery, a JavaScript library that is helpful for interacting with html. Whenever you see a function call with a leading dollar sign, that is jQuery at work

In this article, you'll learn how to build minesweeper using JavaScript, HTML and CSS. I also used jQuery, a JavaScript library that is helpful for interacting with html. Whenever you see a function call with a leading dollar sign, that is jQuery at work

If you want to learn how to build minesweeper with JavaScript, the first step is understanding how the game works. Let’s jump right in and talk about the rules.

Rules of the Game
  1. The minesweeper board is a 10 x 10 square. We could make it other sizes, like the classic Windows version, but for demonstration purposes we will stick to the smaller, “beginner” version of the game.
  2. The board has a predetermined number of randomly placed mines. The player cannot see them.
  3. Cells can exist in one of two states: opened or closed. Clicking on a cell opens it. If a mine was lurking there, the game ends in failure. If there is no mine in the cell, but there are mines in one or more of its neighboring cells, then the opened cell shows the neighboring mine count. When none of the cell’s neighbors are mined, each one of those cells is opened automatically.
  4. Right clicking on a cell marks it with a flag. The flag indicates that the player knows there is a mine lurking there.
  5. Holding down the ctrl button while clicking on an opened cell has some slightly complicated rules. If the number of flags surrounding the cell match its neighbor mine count, and each flagged cell actually contains a mine, then all closed, unflagged neighboring cells are opened automatically. However, if even one of these flags was placed on the wrong cell, the game ends in failure.
  6. The player wins the game if he/she opens all cells without mines.
Data Structures

Cell

JavaScript code representing a minesweeper cell.

Each cell is an object that has several properties:

  • id: A string containing the row and column. This unique identifier makes it easier to find cells quickly when needed. If you pay close attention you will notice that there are some shortcuts I take related to the ids. I can get away with these shortcuts because of the small board size, but these techniques will not scale to larger boards. See if you can spot them. If you do, point them out in the comments!
  • row: An integer representing the horizontal position of the cell within the board.
  • column: An integer representing the vertical position of the cell within the board.
  • opened: This is a boolean property indicating whether the cell has been opened.
  • flagged: Another boolean property indicating whether a flag has been placed on the cell.
  • mined: Yet another boolean property indicating whether the cell has been mined.
  • neighborMineCount: An integer indicating the number of neighboring cells containing a mine.

Board

JavaScript code representing our game board.

Our board is a collection of cells. We could represent our board in many different ways. I chose to represent it as an object with key value pairs. As we saw earlier, each cell has an id. The board is just a mapping between these unique keys and their corresponding cells.

After creating the board we have to do two more tasks: randomly assign the mines and calculate the neighboring mine counts. We’ll talk more about these tasks in the next section.

Algorithms

Randomly Assign Mines

JavaScript code for randomly assigning mines to cells.

One of the first things we have to do before a game of minesweeper can be played is assign mines to cells. For this, I created a function that takes the board and the desired mine count as parameters.

For every mine we place, we must generate a random row and column. Furthermore, the same row and column combination should never appear more than once. Otherwise we would end up with less than our desired number of mines. We must repeat the random number generation if a duplicate appears.

As each random cell coordinate is generated we set the *mined *property to true of the corresponding cell in our board.

I created a helper function in order to help with the task of generating random numbers within our desired range. See below:

Helper function for generating random integers.

Calculate Neighbor Mine Count

JavaScript code for calculating the neighboring mine count of each cell.

Now let’s look at what it takes to calculate the neighboring mine count of each cell in our board.

You’ll notice that we start by looping through each row and column on the board, a very common pattern. This will allow us to execute the same code on each of our cells.

We first check if each cell is mined. If it is, there is no need to check the neighboring mine count. After all, if the player clicks on it he/she will lose the game!

If the cell is not mined then we need to see how many mines are surrounding it. The first thing we do is call our **getNeighbors **helper function, which returns a list of ids of the neighboring cells. Then we loop through this list, add up the number of mines, and update the cell’s *neighborMineCount *property appropriately.

Won’t you be my neighbor?

Let’s take a closer look at that **getNeighbors **function, as it will be used several more times throughout the code. I mentioned earlier that some of my design choices won’t scale to larger board sizes. Now would be a good time to try and spot them.

JavaScript code for getting all of the neighboring ids of a minesweeper cell.

The function takes a cell id as a parameter. Then we immediately split it into two pieces so that we have variables for the row and the column. We use the **parseInt **function, which is built into the JavaScript language, to turn these variables into integers. Now we can perform math operations on them.

Next, we use the row and column to calculate potential ids of each neighboring cell and push them onto a list. Our list should have eight ids in it before cleaning it up to handle special scenarios.

A minesweeper cell and its neighbors.

While this is fine for the general case, there are some special cases we have to worry about. Namely, cells along the borders of our game board. These cells will have less than eight neighbors.

In order to take care of this, we loop through our list of neighbor ids and remove any id that is greater than 2 in length. All invalid neighbors will either be -1 or 10, so this little check solves the problem nicely.

We also have to decrement our index variable whenever we remove an id from our list in order to keep it in sync.

Is it mined?

Okay, we have one last function to talk about in this section: isMined.

JavaScript function that checks if a cell is mined.

The **isMined **function is pretty simple. It just checks if the cell is mined or not. The function returns a 1 if it is mined, and a 0 if it is not mined. This feature allows us to sum up the function’s return values as we call it repeatedly in the loop.

That wraps up the algorithms for getting our minesweeper game board set up. Let’s move on to the actual game play.

Opening A Cell

JavaScript code that executes when a minesweeper cell is opened.

Alright let’s dive right into this bad boy. We execute this function whenever a player clicks on a cell. It does a lot of work, and it also uses something called recursion. If you are unfamiliar with the concept, see the definition below:

Recursion: See recursion.

Ah, computer science jokes. They always go over so well at bars and coffee shops. You really ought to try them out on that cutie you’ve been crushing on.

Anyways, a recursive function is just a function that calls itself. Sounds like a stack overflow waiting to happen, right? That’s why you need a base case that returns a value without making any subsequent recursive calls.

Our function will eventually stop calling itself because there will be no more cells that need to be opened. We could have written this code without recursion, but I thought you all might want to see an example of it in action.

Handle Click Explained

The **handleClick **function takes a cell id as a parameter. We need to handle the case where the player pressed the ctrl button while clicking on the cell, but we will talk about that in a later section.

Assuming the game isn’t over and we are handling a basic left click event, there are a few checks we need to make. We want to ignore the click if the player already opened or flagged the cell. It would be frustrating for the player if an inaccurate click on an already flagged cell ended the game.

If neither of those are true then we will proceed. If a mine is present in the cell we need to initiate the game over logic and display the exploded mine in red. Otherwise, we will open the cell.

If the opened cell has mines surrounding it we will display the neighboring mine count to the player in the appropriate font color. If there are no mines surrounding the cell, then it is time for our recursion to kick in. After setting the background color of the cell to a slightly darker shade of gray, we call **handleClick **on each unopened neighboring cell without a flag.

Helper Functions

Let’s take a look at the helper functions we are using inside the **handleClick **function. We’ve already talked about getNeighbors, so we’ll skip that one. Let’s start with the **loss **function.

JavaScript code that gets called whenever the player has lost the game.

When a loss occurs, we set the variable that tracks this and then display a message letting the player know that the game is over. We also loop through each cell and display the mine locations. Then we stop the clock.

Second, we have the **getNumberColor **function. This function is responsible for giving us the color corresponding to the neighboring mine count.

JavaScript code that gets passed a number and returns a color.

I tried to match up the colors just like the classic Windows version of minesweeper does it. Maybe I should have used a switch statement, but I already took the screen shot, and it’s not really a big deal. Let’s move on to what the code looks like for putting a flag on a cell.

Flagging A Cell

JavaScript code for putting a flag on a minesweeper cell.

Right clicking on a cell will place a flag on it. If the player right clicks on an empty cell and we have more mines that need to be flagged we will display the red flag on the cell, update its flagged property to true, and decrement the number of mines remaining. We do the opposite if the cell already had a flag. Finally, we update the GUI to display the number of mines remaining.

Opening Neighboring Cells

JavaScript code for handling ctrl + left click

We have covered the actions of opening cells and marking them with flags, so let’s talk about the last action a player can take: opening an already opened cell’s neighboring cells. The **handleCtrlClick **function contains the logic for this. This player can perform this action by holding ctrl and left clicking on an opened cell that contains neighboring mines.

The first thing we do after checking those conditions is build up a list of the neighboring flagged cells. If the number of flagged cells matches the actual number of surrounding mines then we can proceed. Otherwise, we do nothing and exit the function.

If we were able to proceed, the next thing we do is check if any of the flagged cells did not contain a mine. If this is true, we know that the player predicted the mine locations incorrectly, and clicking on all of the non-flagged, neighboring cells will end in a loss. We will need to set the local *lost *variable and call the **loss **function. We talked about the **loss **function earlier in the article.

If the player did not lose, then we will need to open up the non-flagged neighboring cells. We simply need to loop through them and call the **handleClick **function on each. However, we must first set the *ctrlIsPressed *variable to false to prevent falling into the **handleCtrlClick **function by mistake.

Starting A New Game

We are almost done analyzing all of the JavaScript necessary to build minesweeper! All that we have left to cover are the initialization steps necessary for starting a new game.

JavaScript code for initializing minesweeper

The first thing we do is initialize a few variables. We need some constants for storing the html codes for the flag and mine icons. We also need some constants for storing the board size, the number of mines, the timer value, and the number of mines remaining.

Additionally, we need a variable for storing if the player is pushing the ctrl button. We utilize jQuery to add the event handlers to the document, and these handlers are responsible for setting the *ctrlIsPressed *variable.

Finally, we call the **newGame **function and also bind this function to the new game button.

Helper Functions

JavaScript code for starting a new game of minesweeper.

Th **newGame **function is responsible for resetting our variables so that our game is in a ready-to-play state. This includes resetting the values that are displayed to the player, calling initializeCells, and creating a new random board. It also includes resetting the clock, which gets updated every second.

Let’s wrap things up by looking at initializeCells.

JavaScript code for attaching click handlers to cells and checking for the victory condition.

The main purpose of this function is to add additional properties to our html game cells. Each cell needs the appropriate id added so that we can access it easily from the game logic. Every cell also needs a background image applied for stylistic reasons.

We also need to attach a click handler to every cell so that we can detect left and right clicks.

The function that handles left clicks calls handleClick, passing in the appropriate id. Then it checks to see if every cell without a mine has been opened. If this is true then the player has won the game and we can congratulate him/her appropriately.

The function that handles right clicks calls handleRightClick, passing in the appropriate id. Then it simply returns false. This causes the context menu not to pop up, which is the default behavior of a right click on a web page. You wouldn’t want to do this sort of thing for a standard business CRUD application, but for minesweeper it is appropriate.

Conclusion

Congrats on learning how to build minesweeper with JavaScript! That was a lot of code, but hopefully it makes sense after breaking it up into modules like this. We could definitely make more improvements to this program’s reusability, extensibility, and readability. We also did not cover the HTML or CSS in detail. If you have questions or see ways to improve the code, I’d love to hear from you in the comments!