Introduction to DHTML

History of DHTML

There was a growth of javascript in 1997, and DHTML was a crucial combination of HTML, Javascript, the newly released CSS standard, and an emerging web programming model called the Document Object Model. As the popularity of javascript grew, developers explored ways to use it in combination with other technologies, which led to the development of DHTML. It became more popular in the late 1990s and early 2000s, but its use declined when AJAX (asynchronous javascript and XML) and other new technologies came.

Need of DHTML

DHTML is an essential technology for web developers. It helps create an interactive and dynamic website. It is built on top of standard web technologies such as HTML, CSS, and Javascript. 

Using DHTML provides users with a more engaging and interactive experience.

We know that traditionally web pages were static. Here, Static means that when a web age is made of “fixed code,” nothing is changed in the website unless a developer makes some changes. It helps create an interactive user interface where a website can adapt according to a user's needs.

DHTML also plays a crucial role in making a responsive website, which means a website can adapt to different screens, such as a laptop, mobile, or tab screen.

DHTML’s ability to create animations and visual effects adds next-level visual appeal to a website.

Why Use DHTML?

• Dynamic Content: DHTML allows for the creation of dynamic and interactive web pages.
• Enhanced User Experience: With DHTML, web pages can respond to user actions in real-time, providing a more engaging experience.
• Reduced Server Load: DHTML enables client-side scripting, reducing the need for server requests and thereby decreasing server load.
• Faster Page Load Times: By dynamically updating content without full page reloads, DHTML can significantly improve page load times.
• Richer User Interfaces: DHTML enables the creation of rich user interfaces with features like drag-and-drop, animations, and interactive forms.
• Cross-Browser Compatibility: DHTML is supported by most modern web browsers, ensuring compatibility across different platforms and devices.

Difference between HTML and DHTML

Drawbacks of HTML

Below are the drawbacks of HTML.

• Using HTML solely, we cannot produce dynamic output.
  
   
• Errors in HTML can prove costly, as even a mistake in closing a tag can make the whole webpage structure go upside down.
  
   
• Creating even a simple webpage requires a lot of code.
  
   
• HTML offers limited security features.
  
   
• We can only create static web pages using HTML.
  
   
• As HTML was designed for desktop browsers, We cannot provide efficient responsiveness to our website by solely using HTML.
  
   
• HTML supports basic animations using CSS, but we cannot create more appealing animations and visual effects. To do so, we would require other modern web technologies and frameworks.

How will DHTML be able to overcome those

DHTML can overcome the limitations of HTML by using the technologies such as CSS, HTML, and Javascript. As HTML provides structure, CSS gives styling, and Javascript provides functionality.

Using DHTML, we can create a dynamic and engaging website using Javascript, which validates the user input and helps in providing instant feedback as we fill out the form. 

Without DHTML, our web pages would only have limited features and a simple user interface. Take an example of a shopping website that how we can add an item to our cart by clicking on “add to cart” button and how we can navigate through different web pages with different information.

DHTML Components 

HTML 4.0

• It stands for hypertext markup language.
  
   
• It is used to give structure to our webpage.
  
   
• HTML 4. O is an HTML version with several new features like scripting languages, style sheets, multimedia options, and better printing facilities.
   

CSS

• CSS stands for cascading style sheets.
  
   
• It handles an image's alignment size and border in a  blog or post.
  
   
• It’s like a group of instructions that gives structure and style to our webpage.
  
   
• CSS is used to provide style to our webpage by designing HTML tags.
  
   
• It adds fonts, colors, and layouts to our webpage.
  
   
• Using CSS, we can also create animations by using “@keyframes.” It is used for controlling intermediate steps in a CSS animation sequence.
   

Javascript
 

• As we have provided structure and design to our website, the next step involves providing functionality to our webpage.
  
   
• Using Javascript, we can add interactivity and dynamic functionality to our web pages.
  
   
• It helps us in executing complex actions.
  
   
• Using Javascript, we can enable the interaction of websites with visitors.
  
   
• We can also load the content in a document without reloading the webpage.
  
   
• Using plugins is made more accessible by javascript. They extend the functionality of a webpage.

DOM(Document Object Model)
 

• It is a programming interface for accessing and manipulating HTML elements.
  
   
• Using DOM, we can interact with the content and structure of a webpage.
  
   
• When a webpage is loaded, a document object model is created by the browser.
  
   
• The HTML DOM model is like a tree of objects.
  
   
• Using the object model, javascript gets the power for creating dynamic HTML. Therefore javascript can change all the HTML elements and attributes, CSS styles, remove existing HTML elements and attributes, add new HTML existing elements and attributes, and can react to all existing HTML events in the page using DOM

Uses of DHTML

DHTML stands for dynamic hypertext markup language, a mixture of technologies such as HTML, CSS, and javascript where. HTML provides structure to a webpage, CSS gives visual effects, and Javascript is used for functionalities. Below are some of the uses of DHTML.
 

• Enhancing Visual effects

DHTML helps to dynamically change the appearance and content of web pages.DHTML helps in creating a responsive and interactive website.
 

• Improved navigation

DHTML is instrumental in creating dropdown, fly-out menus, and other navigation elements that provide a more user-friendly and intuitive interface.
 

• User interactive websites

Using DHTML provides users with a more engaging and interactive experience. We know that traditionally web pages were static, but DHTML helped make a webpage more interactive by enabling certain features which gave a user control over the webpage. This means giving your webpage certain options through which a user can actually interact with the content. For example, a shopping website or a real-time chatting site.
 

• Dynamic Content

Using DHTML, we can create a dynamic and engaging website. We can dynamically change the appearance and content of web pages according to the user's needs. Using Javascript, we can manipulate the web page’s content.
 

• Validation of User Input

Using DHTML, we can validate user input on web forms. This helps in ensuring that the user provides correct information. For instance, we can use DHTML to validate phone numbers, email addresses, and other input types and provide feedback to the user in case any correction is needed.
 

Time for an Example

Now let's look into an example of how DHTML can create an impact. For instance, consider a web page that has a list of checkboxes. Now user can select items by checking the corresponding checkboxes and able to submit the selected items.

Without DHTML

Now if we want to implement this feature without DHTML, the code would look something like this:

In the example below, if we want to select all the items, we would have to select all the items individually. We can also see that it has no styling.

<!DOCTYPE html>
<html>
 <head>
   <title>Example Without DHTML</title>
 </head>
 <body>
   <h1>Skills</h1>
   <ul>
     <li>
       <input type="checkbox" name="item1" value="Full Stack
       Developer" />Full Stack
       Developer
     </li>
     <li>
       <input type="checkbox" name="item2" value="Front-end Developer" />Front-end Developer
     </li>
     <li>
       <input type="checkbox" name="item3" value="Back-end Developer" />Back-end Developer
     </li>
     <li>
       <input type="checkbox" name="item4" value="Blockchain Developer" />Blockchain
       Developer
     </li>
     <li>
       <input type="checkbox" name="item5" value="Game Developer" />Game Developer
     </li>
   </ul>
   <input id=”submit-button” type="submit" value="Submit" />
 </body>
</html>

With DHTML

<!DOCTYPE html>
<html lang="ro">
 <head>
   <meta charset="UTF-8" />
   <link rel="stylesheet" href="./assets/style.css" />
   <meta name="viewport" content="width=device-width, initial-scale=1.0" />
   <title>Skills of a Ninja</title>
 </head>
 <body>
   <h1>Skills</h1>
   <input type="checkbox" id="select-all" /> Select All
   <input type="checkbox" id="select-none" /> Select None
   <ul>
     <li>
       <input
         type="checkbox"
         class="item-checkbox"
         name="item1"
         value="Fullstack Developer"
       />
       Fullstack Developer
     </li>
     <li>
       <input
         type="checkbox"
         class="item-checkbox"
         name="item2"
         value="Front-end Developer"
       />
       Front-end Developer
     </li>
     <li>
       <input
         type="checkbox"
         class="item-checkbox"
         name="item3"
         value="Back-end Developer"
       />
       Back-end Developer
     </li>
     <li>
       <input
         type="checkbox"
         class="item-checkbox"
         name="item4"
         value="Blockchain Developer"
       />
       Blockchain Developer
     </li>
     <li>
       <input
         type="checkbox"
         class="item-checkbox"
         name="item5"
         value=" Game Developer"
       />
       Game Developer
     </li>
   </ul>
   <input id="submit-button" type="submit" value="Submit" />
   <script
     src="https://code.jquery.com/jquery-3.6.0.min.js"
     integrity="sha256-/xUj+3OJU5yExlq6GSYGSHk7tPXikynS7ogEvDej/m4="
     crossorigin="anonymous"
   ></script>


   <script src="assets/javascript.js"></script>
 </body>
</html>



CSS styling:


* {
 font-family: cursive;
 background-color: cornsilk;
}


/* styling the item checkboxes */
.item-checkbox {
 margin-right: 10px;
}


/* styling the "Select All" and "Select None" checkboxes */
.select-checkbox {
 margin-right: 10px;
}


/* "Submit" button style */
#submit-button {
 margin-top: 10px;
 padding: 5px 10px;
 background-color: #203246;
 color: #fff;
 border: none;
 border-radius: 10px;
 cursor: pointer;
}


/* styling "Submit" button when the mouse hovers over it */
#submit-button:hover {
 background-color: #0069d9;
}

Javascript functionality

/* eslint-disable no-undef*/


// for all the "Select All" checkbox
var selectAll = document.getElementById('select-all');


// for all the "Select None" checkbox
var selectNone = document.getElementById('select-none');


//  item checkboxes
var itemCheckboxes = document.querySelectorAll('.item-checkbox');


// adding an event listener to the "Select All" checkboxes
selectAll.addEventListener('click', function () {
 // checking all the unchecked items
 for (var i = 0; i < itemCheckboxes.length; i++) {
   itemCheckboxes[i].checked = true;
 }
});


// adding an event listener to the "Select None" checkbox
selectNone.addEventListener('click', function () {
 // unchecking all the checked items
 for (var i = 0; i < itemCheckboxes.length; i++) {
   itemCheckboxes[i].checked = false;
 }
});


// adding an event listener to the "Submit" button
var submitButton = document.getElementById('submit-button');
submitButton.addEventListener('click', function () {
 // creating an empty array to store the selected items
 var selectedItems = [];
 for (var i = 0; i < itemCheckboxes.length; i++) {
   // adding all the checked items to the selectedItems array
   if (itemCheckboxes[i].checked) {
     selectedItems.push(itemCheckboxes[i].value);
   }
 }
 // creating a string that consists of selected items, separated by commas
 var selectedItemsString = selectedItems.join(', ');
 if (selectedItems.length === 0) alert('Please select an option');
 else alert('You have selected: ' + selectedItemsString);
});

We have modified our plain blank web page by adding some styling and functionality. In the above example, we have changed the styling. Without DHTML, we would have to select all the items individually and to de-select them all we would have to do to each item individually to de-select them all.

But with DHTML, we can create a function that checks all the unchecked items without us having to go to each one separately, and the same can be done for “Select-None.”
 

• When we select individual items and click on the submit button:

alert() displays the following message:

• Submitting all the items using the “select all” functionality:

 
alert() displays the following message:

• Submitting an empty list:

alert() displays the following message when we submit an empty list:

DHTML Features

Below are some of the features of DHTML.
 

Object-oriented view

We can create an object-oriented view of the webpage using DHTML. A web page can be dynamically manipulated and updated without reloading it. Therefore we can create more responsive and interactive websites using DHTML.
 

CSS(Cascading Style Sheets) and layering of content 

We can use CSS to enhance our websites' visual appeal. We can also layer content on top of each other.
 

Dynamic Fonts

We can use dynamic fonts on our web pages. These can be resized and formatted upon the user’s preferences.
 

Dynamic Content

Dynamic content refers to how we can change the content of a webpage without reloading it. Some examples of dynamic content are online shopping sites, chatting sites, data visualizers, live locations, etc.

Example:

Consider another example where we automatically change a box's color every 1 second using javascript's setTimeout() function. 

Code:

<!DOCTYPE html>
<html>
 <head>
     <link href="https://fonts.googleapis.com/css?family=Montserrat&display=swap" rel="stylesheet">
   <title>Object-oriented View using DHTML</title>
   <style>
     * {
       background-color: rgb(173, 138, 89);
       /* font-family: cursive; */
       /* if we will set the font family 'cursive' globally, it will override the specific rule
       that we will apply later on using js */
     }


     .box {
       top: 10%;
       left: 30%;
       justify-content: center;
       width: 50%;
       height: 30%;
       position: absolute;
       background-color: orange;
       position: absolute;
       border-radius: 9%;
     }
     .text {
       display: flexbox;
       position: absolute;
       top: 30%;
       left: 5%;
       background-color: orange;
       border-radius: 40%;
       justify-items: center;
       justify-content: center;
     }
     p {
       display: flex;
       border-radius: 90%;
       background-color: orange;
     }
   </style>
   <script>
     var btn = document.getElementById('btn');
     function changeColorAndFont() {
     
       var box = document.getElementById('box');
       if (box.style.backgroundColor == 'orange') {
         box.style.backgroundColor = 'yellow';
         box.style.fontFamily='cursive';
    
       } else {
         box.style.backgroundColor = 'orange';
         box.style.fontFamily='montserrat';


       }
       setTimeout(changeColorAndFont, 1000);
     }
   </script>
 </head>
 <body onload="changeColorAndFont()">
   <div class="box" id="box">
     <div class="text"><p class="mssg"">Hi Ninja! Notice color and font change</p></div>
   </div>
 </body>
</html>

Output:

Explanation:

In the code below, we have made a box using HTML’s <div> tag, and to dynamically change its color and the font’s text displayed after each second, we are making use of CSS selectors and the concept of DOM manipulation.

We are using CSS for styling the HTML elements like font family, background color, position,border-radius, height/ width of the box, and text.

The Javascript is being used for creating a dynamic effect i.e. how the box’s background color and font family is changing after an interval. We have used the setTimeout() method and repeatedly called the changeColorAndFont() function after each second for changing the color and font family.

The setTimeOut() is a built-in javascript method using which we can execute a specific function or a code block after a specified delay in milliseconds.

Also see, Queryselectorall

DHTML Events

An event refers to an action or occurrence in a browser. For instance, when we click on a button or when we scroll. Events change the appearance of elements on the page or trigger scripts. For example, when we click on a button on a webpage, there is a change in the color of a specific HTML element, or there are events related to the mouse’s action, such as when we scroll on a webpage and an event occurs on the webpage. We can also create some scroll animations using this property.

Below are some of the types of events.
 

Types of events:
 

Window Events: These events get triggered when the state of the window changes. Some examples of window events are mentioned below.
 

• scroll: It gets triggered whenever we scroll the window.
  
   
• resize: resize events are triggered when the user changes the size of the window.
  
   
• load: This event is triggered when the window has finished loading all resources.
   

Document Events: Document events are related to the webpage’s content. They are triggered when the state of the document changes.
 

• Keyboard Events-Theses are the events related to keyboard activities, such as when we press a key on the keyboard and a change occurs on our webpage. For instance, when we press enter, we can submit a form on the website.
  
   
• click-These are the events triggered when the user clicks on an HTML element, i.e., when a user clicks on an image, button, or a link.
  
   
• Form Submission Events-These events get triggered when we submit a form.
   

Example of Event Handlers
 

There are several event handlers; below are some of the major ones.

DHTML Applications

The applications of DHTML are as follows.

• Creating Dynamic Menus: Using DHTML, we can create dynamic menus which can respond to the user’s input.
  
   
• Animations: We can create animations ad add them to our websites. For instance, we can use scroll animations, where the content of the webpage changes upon scrolling through the webpage. We can also use @keyframes in CSS to create amazing animations and transitions.
  
   
• Games: We can also create games with DHTML which can be displayed in the browser.For example, a snake game or a flappy bird game.
  
   
• Interactive UI: Using DHTML, we can create a smooth interaction with the website by creating visual feedback according to the user’s action or changes between application statuses.
  
   
• Navigation: It refers to a website’s section that helps the user in traveling through the website, like navigating from one part of the website to another. This can be done by creating a dynamic navigation bar, ceratin animation, or effects that can guide the user.

DHTML DOM

DHTML DOM, or Dynamic HTML Document Object Model, refers to the manipulation and interaction of HTML elements in real-time using JavaScript and CSS. It allows developers to dynamically update and modify the content, structure, and styling of web pages without requiring full page reloads. With DHTML DOM, developers can create rich and interactive user experiences by accessing and manipulating elements, attributes, and styles on the fly. This dynamic interaction enhances the responsiveness and functionality of web applications, enabling features such as drag-and-drop, animations, form validation, and more.

DHTML Advantages

The advantages of DHTML are as follows.

• Interactive UI: DHTML helps provide an interactive user interface to our web pages.
  
   
• Compact File Size: DHTML is compact compared to other multimedia software like Shockwave and Flash. This saves bandwidth and time.
  
   
• Dynamic content: It has a major plus point that we can dynamically change the appearance and content of web pages according to the user's needs. 
  
   
• Cross-Browser Compatibility: DHTML is compatible with all modern web browsers, i.e., they all support DHTML. 
  
   
• Efficient: DHTML is efficient, and the files are maintainable, which means that web designers have more flexibility due to DHTML.
  
   
• Less Server Load: As we can create dynamic web pages using DHTML, it helps in reducing server load and improves overall performance.

DHTML Disadvantages

The disadvantages of DHTML are as follows.

• As we have discussed, DHTML uses various technologies. Therefore, it is advised to have a good command of them.
   
• We need to check browser compatibility while using DHTML as it is not sure that it will perform on each and every platform.
   
• Maintaining  DHTML code can be a tedious task.

Frequently Asked Questions

What are the applications of DHTML?

DHTML has many applications. Using DHTML provides users with a more engaging and interactive experience. A web page can be dynamically manipulated and updated without reloading it. Therefore we can create more responsive and interactive websites using DHTML. For example, a shopping website, a video streaming, or a gaming website.

What type of language is DHTML?

DHTML is not a programming language itself. Instead, it is a combination of technologies used in web development. DHTML uses HTML (for structure), CSS (for styling), and JavaScript (for behavior) to create interactive and dynamic web pages.

What is the difference between DHTML and XML?

DHTML (Dynamic HTML) is for interactive web pages with HTML, CSS, and JavaScript. XML (eXtensible Markup Language) organizes data with tags, primarily for structured data representation and interchange, not for web page interactivity.

What are the four components of DHTML?

The four components of DHTML are HTML, CSS(cascading style sheet), Javascript(client-side scripting language), and DOM(document object model). HTML is used to structure our webpage, while CSS gives styling and layout, and Javascript gives functionality to our webpage. DOM is a programming interface for accessing and manipulating HTML elements. Using DOM, we can interact with the content and structure of a webpage.

Conclusion

We hope that this article helped you in understanding DHTML. In this article, we have discussed what DHTML is, why we need it, its components, and its uses. We have also outlined its key features by providing an example. Moving on, we have also discussed its applications, advantages, and disadvantages.