Javascript как добавить кнопку

Для отправки введенных данных на форме используются кнопки. Для создания кнопки используется либо элемент button :

С точки зрения функциональности в html эти элементы не совсем равноценны, но в данном случае они нас интересуют с точки зрения взаимодействия с кодом javascript.

При нажатии на любой из этих двух вариантов кнопки происходит отправка формы по адресу, который указан у формы в атрибуте action , либо по адресу веб-страницы, если атрибут action не указан. Однако в коде javascript мы можем перехватить отправку, обрабатывая событие click

При нажатии на кнопку происходит событие click , и для его обработки к кнопке прикрепляем обработчик sendForm . В этом обработчике проверяем введенный в текстовое поле текст. Если его длина больше 5 символов, то выводим сообщение о недостимой длине и прерываем обычный ход события с помощью вызова e.preventDefault() . В итоге форма не отправляется.

Если же длина текста меньше шести символов, то также выводится сообщение, и затем форма отправляется.

Также мы можем при необходимости при отправке изменить адрес, на который отправляются данные:

function sendForm(e)< // получаем значение поля key var keyBox = document.search.key; var val = keyBox.value; if(val.length>5) < alert("Недопустимая длина строки"); document.search.action="PostForm"; >else alert("Отправка разрешена"); >

В данном случае, если длина текста больше пяти символов, то текст отправляется, только теперь он отправляется по адресу PostForm , поскольку задано свойство action:

document.search.action="PostForm";

Для очистки формы предназначены следующие равноценные по функциональности кнопки:

При нажатию на кнопки произойдет очистка форм. Но также функциональность по очистке полей формы можно реализовать с помощью метода reset() :

function sendForm(e)< // получаем значение поля key var keyBox = document.search.key; var val = keyBox.value; if(val.length>5) < alert("Недопустимая длина строки"); document.search.reset(); e.preventDefault(); >else alert("Отправка разрешена"); >

Кроме специальных кнопок отправки и очистки на форме также может использоваться обычная кнопка:

При нажатии на подобную кнопку отправки данных не происходит, хотя также генерируется событие click:

При нажатии на кнопку получаем введенный в текстовое поле текст, создаем новый элемент параграфа для этого текста и добавляем параграф в элемент printBlock.

Источник

How to Create Button in JavaScript

Developers mostly want their web pages to be attractive and make them interactive. For this purpose, buttons are added to the web page. For instance, when there is a need to send or receive data, including click events for added functionalities for the user while registering or signing in to an account. In such cases, buttons allow the end-user to perform various functionalities smartly.

This blog will explain the methods to create buttons in JavaScript.

How to Create Button in JavaScript?

To create button in JavaScript, the following methods can be utilized:

The following approaches will demonstrate the concept one by one!

Method 1: Create Button in JavaScript Using “createElement()” and “appendChild()” Methods

The “createElement()” method creates an element, and the “appendChild()” method appends an element to the last child of an element. These methods will be applied for creating a button and appending it to the Document Object Model(DOM) that needs to be utilized, respectively.

Syntax

document. createElement ( type )

element. appendChild ( node )

In the above syntax, “type” refers to the type of element that will be created using the createElement() method, and “node” is the node that will be appended with the help of the appendChild() method.

The following example will explain the stated concept.

Example

Firstly, a “button” will be created using the document.createElement() method and stored in a variable named “createButton”:

Next, the “innerText” property will refer to the created button and set the text value of the specified button as follows:

Lastly, the “appendChild()” method will append the created button to DOM by referring to the variable in which it is stored as an argument:

The output of the above implementation will result as follows:

Method 2: Create Button in JavaScript Using “Type” Attribute of “input” Tag

The “type” attribute represents the type of input element to display. It can be used to create a button by specifying “button” as the value of the type attribute of the input tag.

Syntax

Here, “button” indicates the type of the input field.

Check out the below-given example.

Example

Firstly, we will use an input tag, specify its type as “button”, and value as “Click_Me”. As a result, a button will be created. Furthermore, it will trigger the “createButton()” function when clicked:

In the JavaScript file, we will define the “createButton()” function which will generate an alert box when the added button will be clicked:

Output

The discussed techniques to create a button in JavaScript can be utilized suitably according to the requirements.

Conclusion

To create a button in JavaScript, “createElement()” and “appendChild()” methods can be applied for creating a button and appending it to be utilized in the DOM. Another technique that can be used to create a button is defining an input type and adding the associated functionality. This article demonstrated the methods to create a button in JavaScript.

About the author

Sharqa Hameed

I am a Linux enthusiast, I love to read Every Linux blog on the internet. I hold masters degree in computer science and am passionate about learning and teaching.

Источник

JavaScript Button

JavaScript button is one of the JavaScript element which gives effects to web pages. JavaScript buttons give a good look and feel to the website. These JavaScript buttons can be used to send or receive data; fire clicks events, change the color or text, etc. HTML tag is used in JavaScript frameworks that define a clickable button. When a button is rendered onto the web page, an event is fired to perform a functionality. We shall look into the creation of JavaScript buttons by using createElement() and an HTML tag, which is used for JavaScript frameworks.

Web development, programming languages, Software testing & others

Using HTML tag for JavaScript Buttons

Above is the syntax mainly used in JavaScript Frameworks like ReactJs, AngularJs, etc.

varsampleButton = document.createElement(btn);

Above is the Pure JavaScript Syntax used to create a JavaScript button.

Examples of JavaScript Button

Look at the below examples to learn How JavaScript buttons are created?

Example #1

Creating a JavaScript Button using tag

   Creation of a JavaScript Button using HTML tag
 As there is no functionality or any event linked, clicking button will not work

So here, in the above example, we are just creating a button using the HTML tag with an id. Clicking won’t work as there is no event handler or functionality applicable.

Example #2

Add a Click Event to the button.

   Adding onClick event handler for JavaScript Button
 Click below to see the onClick functionality
  function sampleClick()

In the above example, we use the onClick functionality to disable the button. .disabled is the method that helps the button get disabled, and clicking would not work.

Example #3

onClick on a button to display text.

   onClick event on JavaScript Button to display text
 JavaScript element triggers an onClick function
  function clickText()

Example #4

    body < text-align: left; >/* Styling for the btn1 class */ .btn1 < background-color: #4FFF8A; >/* Styling for */ #htmlbtn1 < font-weight: bold; >/* Styling for */ #htmlbtn2 < font-style: italic; >/* Styling for */ #jsbtn JavaScript buttons:

Let us walk through the code to understand it in a much better way,

a document.createElement(‘btn1’); creates clickable button object and referenced as ‘clickBtn.’

innerHTML helps in setting inner content, also known as a label.
id = ‘jsbtn,’ sets button Id
className = ‘btn1’, sets the buttons styling CSS
body.appendChild(clickBtn) helps append clickBtn to the document’s body as a child.

When the page renders, we see all three buttons with background styling from the btn1 class; also, each button has different font styles specific to the ids.

Initially, the text label for htmlbtn2 was ‘I’m an HTML button 2!’; we used JavaScript and modified the text label to ‘Modified HTML button 2!’.

Example #5

   onClick event on button for pop up
 Click the button to see a pop up with text

On click, you will see an alert box,

Example #6

   Displaying Data and Time

On click, we will see the Current Date and Time,

JavaScript buttons can have multiple event handlers applied to them.

on clicking the button
Hover the mouse over the button
on mouse out from the button
on submitting a form/ data by clicking the button (Post method)
Retrieving data from a source (Get method)
Removing the focus from the button
Applying focus on the button
Disabling the button using .disable
On change method
and many more…..

Conclusion

With this, we shall conclude the topic ‘JavaScript button.’ We have discussed JavaScript buttons and their usage. Different ways of describing the button; one is by using JavaScript createElement() and the other by using HTML tag . I have listed some examples with clear explanations to make you understand much better. As we have many event handler methods applicable to JavaScript buttons, we have listed some. You can even try hands-on with the other events. JavaScript buttons make the web page look more elegant, as most essential web pages have buttons with various functionalities.

Javascript как добавить кнопку

JavaScript programmatically create an HTML button

Learn JavaScript for Beginners 🔥

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