Trending February 2024 # How To Use Checkbox Inside Select Option Using Javascript? # Suggested March 2024 # Top 9 Popular

You are reading the article How To Use Checkbox Inside Select Option Using Javascript? updated in February 2024 on the website Minhminhbmm.com. We hope that the information we have shared is helpful to you. If you find the content interesting and meaningful, please share it with your friends and continue to follow and support us for the latest updates. Suggested March 2024 How To Use Checkbox Inside Select Option Using Javascript?

Create a custom select menu Syntax

Users can follow the syntax below to manage the checkboxes of a custom dropdown menu using JavaScript.

function showOptions() { if (showCheckBoxes) { showCheckBoxes = false; } else { showCheckBoxes = true; } } function getOptions() { var selectedOptions = document.querySelectorAll('input[type=checkbox]:checked') }

In the above syntax, we show the options of custom dropdown based on the value of the showCheckBoxes variable. Also, we can iterate through the array of selectedOptions array to get all checked checkboxes one by one.

Steps

Step 1 − Create a div containing the menu text.

Step 2 − Now, use the custom HTML, and make options using the checkbox input type.

Step 4 − In JavaScript, declare the showCheckBoxes variable, and initialize it with the true Boolean value. We will show the options of custom dropdown based on the showCheckBoxes variable.

Step 6 − Now, define a getOptions() function. In the getOptions() function, access all checked checkboxes and print the value of all selected checkboxes by iterating through the selectedOptions array using the for-loop.

Example 1

In the example below, we have created the custom select menu as explained in the above algorithm. Users can select multiple options by checking the multiple checkboxes.

.dropdown { width: 12rem;       height: 1.5rem;       font-size: 1.3rem;       padding: 0.6 0.5rem;       background-color: aqua;       cursor: pointer;       border-radius: 10px;       border: 2px solid yellow; }     #options {       margin: 0.5rem 0;       width: 12rem;       background-color: lightgrey;       display: none;       flex-direction: column;       border-radius: 12px;     }     label {       padding: 0.2rem;     }     label:hover {       background-color: aqua;     }     button {       font-size: 1rem;       border-radius: 10px;       padding: 0.5rem;       background-color: yellow;       border: 2px solid green;       margin: 1rem 0; } show all options       First Option       Second Option       Third Option       Fourth Option       Fifth Option let output = document.getElementById(‘output’);     var showCheckBoxes = true;

    function showOptions() {       var options =         document.getElementById(“options”);

      if (showCheckBoxes) {         options.style.display = “flex”;         showCheckBoxes = !showCheckBoxes;       } else {         options.style.display = “none”;         showCheckBoxes = !showCheckBoxes;       }     }     function getOptions() {       var selectedOptions = document.querySelectorAll(‘input[type=checkbox]:checked’)       for (var i = 0; i < selectedOptions.length; i++) {         output.innerHTML += selectedOptions[i].value + ” , “;         console.log(selectedOptions[i])       }     }

In this tutorial, users learned to create a custom select menu using the html, CSS, and JavaScript. Also, users can use some CSS libraries like Bootstrap to create a select menu with checkboxes.

You're reading How To Use Checkbox Inside Select Option Using Javascript?

How To Make A Text Italic Using Javascript

In this tutorial, we will learn to make a text italic using JavaScript. We give the italic property to a text to differentiate it from other text within the sentence.

In HTML, we can make a text italic by just adding the text within the ‘i’ tag. But sometimes, we have to make it dynamic, that not possible with HTML. Then, we have to use a programming language like JavaScript to make the text italic.

Let’s have a look at how to make a text italic using JavaScript. Following are the ways by which we can make a text italic in JavaScript −

Using String italics() Method.

Using Style fontStyle Property.

By Creating DOM Italic Object.

Using String italics() Method

The italics() method is the method in JavaScript used to make the text italic. It does the same thing that the ‘i’ tag in HTML. This method can be invoked only on the strings. It also does not takes any arguments.

Syntax

All the users can follow the below syntax to use the italics() method to make a text italic using JavaScript −

string.italics();

Example

In the example below, we used the italics() method to make a text italic using JavaScript.

var

text

=

“Welcome to the JavaScript”

;

document

.

getElementById

(

‘para’

)

.

innerHTML

=

text

.

italics

(

)

;

In the above example, users can see that we have used the italics() method to make a text italic using JavaScript.

Using Style fontStyle Property

We can use the fontStyle property of the DOM style to make a text italic. We set this property to string value “italic”.

Syntax

Following is the syntax to make a text italic using HTML DOM style fontStyle property −

document.getElementById("paragraph").style.fontStyle = "italic"; Example

function

italic

(

)

{

document

.

getElementById

(

“paragraph”

)

.

style

.

fontStyle

=

“italic”

;

}

By Creating DOM Italic Object

The DOM(document object model) is a standard in JavaScript to access the elements in the document. We can add or access all elements of HTML through the DOM in JavaScript. We make our text italic in HTML by placing it inside the ‘i’ tag. In the same way, we can add the italic element and append the text inside it through the DOM in JavaScript.

Syntax

All the users can follow the below syntax to use the DOM Objects to make a text italic using JavaScript −

var2.appendChild(var3);

Algorithms

Step-1 − Create an ‘i’ element using DOM.

Step-2 − Create a text node and add text to it.

Step-3 − Append the text node in the ‘i’ element.

Step-4 − Now, append the ‘i’ element to any container element.

Example

function

italic

(

)

{

var

para

=

document

.

getElementById

(

“para”

)

;

var

add_element

=

document

.

createElement

(

‘i’

)

;

var

text

=

document

.

createTextNode

(

para

.

innerHTML

)

;

add_element

.

appendChild

(

text

)

;

para

.

innerHTML

=

“”

;

para

.

appendChild

(

add_element

)

;

}

In this tutorial, we have learned about the two ways by which we can make a text italic in JavaScript. Among these, italics() is the method that makes a string italic. We also have used the DOM Objects to make a text italic using a custom logic in JavaScript. You can use both ways to make a text italic while the italics() is the simplest.

How To Add Rows To A Table Using Javascript Dom?

We will learn how to add a row to a table using JavaScript dom. To achieve this, we have multiple methods. Some of them are the following.

Using the insertRow() method

By creating the new Element

Using the insertRow() Method Syntax table.insertRow(index)

Return value − The element which was inserted.

Below is the syntax to insert cell −

table.insertCell(index)

Return value − The element which was inserted.

Steps to add a row to the table

Get the data table element.

Create a row using the insertRow method and inset it into the table.

Create new cell(s) using the insertCell method and insert them into the row you created.

Add data to the newly created cells.

Example

In this example, we have a table that contains the name of the students and their ages. We are adding a new student at the end of the table.

table

,

td

,

th

{

border

:

1

px solid black

;

}

function

addRow

(

)

{

let

table

=

document

.

getElementById

(

“myTable”

)

;

let

row

=

table

.

insertRow

(

1

)

;

let

c1

=

row

.

insertCell

(

0

)

;

let

c2

=

row

.

insertCell

(

1

)

;

let

c3

=

row

.

insertCell

(

2

)

;

c1

.

innerText

=

“Elon”

c2

.

innerText

=

45

c3

.

innerText

=

“Houston”

}

By Creating New Elements

In this method, we will create new rows and columns by using the document.createElement() method.

Approach

Here are the steps to add a row to a table by creating elements.

Get the table body element in which you want to add a row

Create row element

Create cells Insert data into cells

Append cells to the row

Append row to table body

Example

table

,

td

,

th

{

border

:

1

px solid black

;

}

function

addRow

(

)

{

let

table

=

document

.

getElementById

(

“tableBody”

)

;

let

row

=

document

.

createElement

(

“tr”

)

let

c1

=

document

.

createElement

(

“td”

)

let

c2

=

document

.

createElement

(

“td”

)

let

c3

=

document

.

createElement

(

“td”

)

let

c4

=

document

.

createElement

(

“td”

)

c1

.

innerText

=

“Elon”

c2

.

innerText

=

“42”

c3

.

innerText

=

“Houston”

c4

.

innerText

=

“C++”

row

.

appendChild

(

c1

)

;

row

.

appendChild

(

c2

)

;

row

.

appendChild

(

c3

)

;

row

.

appendChild

(

c4

)

;

table

.

appendChild

(

row

)

}

How To Clone An Object Using Spread Operator In Javascript?

The spread operator, which was first introduced in ES6, is used to unpack the elements of an iterable like an array. Cloning and merging the array is simple thanks to the spread operator. The spread operator could not be used with objects when it was first introduced in ES6. The spread operator was eventually extended to objects in ES2024.

You’ll learn how to use the JavaScript object spread (…) to clone an object or merge two objects into one in this article. In areas where 0+ arguments are expected, the spread operator allows an iterable to extend.

This is most frequently used in variable arrays where more than one value is required. It provides us with the ability to get a list of parameters from an array. The Spread operator has the same syntax as the Rest argument, but it has the exact opposite effect.

When all elements from an object or array must be included in a list of some sort, spread syntax could be used.

Syntax

Following is the syntax of spread operator

var myVariable = [...value]; Example 1

To unpack elements of an array, you use the spread operator (…) in this example. When cloning an array, the spread operator comes very helpful.

let

team

=

[

‘India’

,

‘Australia’

,

‘England’

,

‘New Zealand’

]

;

let

cricket

=

[

team

]

;

document

.

getElementById

(

“result”

)

.

innerHTML

=

cricket

;

Example 2

In his example the spread operator (…) unpacks elements from the team array and sets them in a new array cricket in this example. To combine two or more arrays into one, use the spread operator (…).

let

cricket

=

[

‘India’

,

‘Australia’

,

‘England’

,

‘New Zealand’

]

;

let

bcci

=

[

‘West Indies’

,

‘Ireland’

,

‘Kenya’

,

‘Bangladesh’

]

;

let

merge

=

[

cricket

,

bcci

]

;

document

.

getElementById

(

“result”

)

.

innerHTML

=

merge

;

Example 3

In this example, you’ll learn how to utilise the JavaScript Object spread operator to clone an object’s own enumerable properties −

const

cricket

=

{

team

:

14

}

;

const

clonedCricket

=

{

cricket

}

;

document

.

write

(

clonedCricket

.

team

)

;

Example 4

Merging objects: In this example, you’ll learn how the spread operator (…) can be used to merge two objects similarly to arrays.

const

cricket

=

{

team

:

12

}

;

const

style

=

{

backgroundColor

:

“blue”

}

;

const

solidCircle

=

{

cricket

,

style

}

;

document

.

getElementById

(

“result1”

)

.

innerHTML

=

solidCircle

.

team

;

document

.

getElementById

(

“result2”

)

.

innerHTML

=

solidCircle

.

backgroundColor

;

console

.

log

(

solidCircle

)

;

Example 5

The tutpoint1 object is being shared. The tutpoint1 object’s key-value pairs are copied to the clonedUser object. Let’s take a look at another example of merging two objects with the spread operator − mergedUsers is a clone of both tutpoint1 and tutpoint2. Each countless property on the objects will be copied to the mergedUsers object in fact. The spread operator is really a shortcut for the Object.assign() function, however there are several variations.

const

tutpoint1

=

{

country

:

‘India’

,

tutorial

:

‘Tutorialspoint’

,

}

;

const

tutpoint2

=

{

name

:

“JavaScript”

,

framework

:

“React JS”

}

;

const

mergedUsers

=

{

tutpoint1

,

tutpoint2

}

;

console

.

log

(

mergedUsers

)

In Brief

The spread operator, the rest operator, and the Object.assign() function are all acceptable ways to clone objects in JavaScript. In addition to cloning objects, object spread and Object.assign() allow you to add or edit properties as the clone is being created.

You can clone an object while adding, updating, or skipping properties from being cloned by combining the object spread and rest in a same line. The spread operator creates new properties whereas Object.assign() assigns them when merging objects.

How To Use Spread Syntax With Arguments In Javascript Functions?

We use the Spread Syntax of JavaScript to expand an array, string, or object in place. Such types of values are called iterable. This is similar to destructuring the iterable in place. Its utility in a function call allows us to extract function parameters from an iterable. In this tutorial, we learn how to use Spread Syntax with arguments in JavaScript functions.

Spread operator in JavaScript

A Spread operator, denoted with (…) followed by the name of the iterable expands the iterable into its constituent elements.

e.g.

const [x, y, ...z] = [1, 2, 3, 4, 5]

This creates three variables x, y, and z. The first two values are stored in the corresponding variables. So, x = 1, y = 2, and z = [3, 4, 5].

The spread operator stores the rest of the iterable into the z variable.

It is most commonly used in function calls to expand the iterable at the time of parameter initialization.

Example 1

Here we are going to show the use of the spread operator in the function call. We will create an array of strings and pass it as a function argument for printing. Let’s look at the code for the same.

function

print

(

a

,

b

,

c

)

{

}

var

arr

=

[

“first”

,

“second”

,

“third”

]

print

(

arr

)

In the above code, the variables take the corresponding values from the array. This happens in order. So a = arr[0], b = arr[1] and c = arr[2].

The spread operator can be used to handle cases in which only some part of the iterable list is useful, and the rest can be ignored. The example from the beginning emphasizes that use case.

Let us look at an example to see this use case.

Example 2

Here we are going to show the use of the spread operator in the function call. We will create an array of strings and pass it as a function argument for printing. In this example, however, we will emphasize only the first element in the list.

function

print

(

f

,

rest

)

{

}

var

arr

=

[

“first”

,

“second”

,

“third”

,

“fourth”

]

print

(

arr

)

Only the first element is put to use, and the rest of the elements can be put into a different variable using the spread operator. This also provides us the utility of handling cases in which we have no information on the upper bound of the size of the iterable, but we know the lowest size.

The spread operator can also be used with objects. Note however that the spread operator provides an easy way to copy an iterable. This copy is separate from the original iterable, and any changes in the new copy are not reflected in the original one.

The spread operator can also concatenate iterable in the function call.

Here’s an example −

Example 3

Here we will create two separate lists of strings and use the spread operator to concatenate the two lists when calling the function.

function

print

(

arr

)

{

var

text

=

“”

;

for

(

var

i

=

0

;

i

<

arr

.

length

;

i

++

)

text

+=

arr

[

i

]

+

“,”

;

document

.

getElementById

(

“result”

)

.

innerHTML

=

text

}

var

arr

=

[

“first”

,

“second”

,

“third”

,

“fourth”

]

var

rest

=

[

“fifth”

,

“sixth”

,

“seventh”

]

print

(

[

arr

,

rest

]

)

Here we are passing a concatenated list of the two arrays as the argument for the function call print(). The spread operator expands both lists and creates a new list that acts as a single complete argument.

Conclusion

The Spread operator is pretty useful for single-dimensional arrays or iterable but is unsuitable for multidimensional iterable. It can also be used with objects.

Manipulating Dom Using Service Workers In Javascript

Service Workers are JavaScript files that run in the background of a web application independently of the web page. They provide a way to intercept and handle network requests, cache resources, and manipulate the DOM. In this article, we will dive into how to use service workers to manipulate the DOM in JavaScript.

The Concept of Service Workers

Service Workers are a part of the Web API that enables developers to write scripts that intercept and control network requests from web pages. They run in a separate thread, independent of the main thread that executes JavaScript in the web page. This separation provides several benefits such as:

Improved performance: Service Workers can cache resources and respond to requests from the cache, reducing the number of network requests and improving the performance of the web application.

Offline capabilities: Service Workers can cache resources and provide a fallback response when the network is not available, enabling the web application to work offline.

Push notifications: Service Workers can receive push notifications from the server and display them to the user, even when the web page is not open.

Manipulating DOM using Service Workers

Service Workers can manipulate the DOM of a web page by intercepting and modifying network requests. The following steps illustrate how to manipulate the DOM using Service Workers:

Register the Service Worker:

To use a Service Worker, we first need to register it in the web page. We can register a Service Worker using the `navigator.serviceWorker.register()` method. The following code snippet illustrates how to register a Service Worker:

if ('serviceWorker' in navigator) { window.addEventListener('load', function() { navigator.serviceWorker.register('/service-worker.js').then(function(registration) { console.log('Service Worker registered with scope:', registration.scope); }, function(err) { console.log('Service Worker registration failed:', err); }); }); }

Intercept network requests:

Once the Service Worker is registered, it can intercept network requests using the `fetch` event. The `fetch` event is triggered whenever a network request is made from the web page. We can add an event listener to the `fetch` event and modify the response before it is returned to the web page. The following code snippet illustrates how to intercept network requests:

self.addEventListener('fetch', function(event) { event.respondWith( fetch(event.request).then(function(response) { return response; }).catch(function() { }) ); });

Modify the response:

Once we intercept the network request, we can modify the response before it is returned to the web page. We can modify the response by cloning it and modifying its properties such as `status`, `headers`, and `body`. The following code snippet illustrates how to modify the response:

self.addEventListener('fetch', function(event) { event.respondWith( fetch(event.request).then(function(response) { var modifiedResponse = response.clone(); modifiedResponse.status = 200; modifiedResponse.headers.set('X-Custom-Header', 'custom-value'); modifiedResponse.text().then(function(text) { chúng tôi = function() { return Promise.resolve(text + ' (modified by Service Worker)'); } }); return modifiedResponse; }).catch(function() { }) ); }); Conclusion

Service Workers provide a way to intercept and handle network requests, cache resources, and manipulate the DOM. By intercepting network requests and modifying the response, we can manipulate the DOM of a web page using Service Workers. This functionality enables us to improve the performance and offline capabilities of web applications.

Update the detailed information about How To Use Checkbox Inside Select Option Using Javascript? on the Minhminhbmm.com website. We hope the article's content will meet your needs, and we will regularly update the information to provide you with the fastest and most accurate information. Have a great day!