Using variable in html code

How to display JavaScript variable value in HTML

This tutorial will show you how to use all three ways to display JavaScript variables in HTML pages. Let’s start with using document.write() method.

Display JavaScript variable using document.write() method

The document.write() method allows you to replace the entire content of HTML tag with HTML and JavaScript expressions that you want to be displayed inside the tag. Suppose you have the following HTML element:

When you run document.write("Hello") method on the HTML piece above, the content of will be replaced as follows:

 Knowing this, you can display any JavaScript variable value by simply passing the variable name as the parameter to document.write() method:

The document.write() method is commonly used only for testing purposes because it will delete any existing HTML elements inside your tag. Mostly, you would want to display a JavaScript variable beside your HTML elements. To do that, you need to use the next method.

Display JavaScript variable using innerHTML property.

Every single HTML element has the innerHTML property which holds the content of that element. The browser allows you to manipulate the innerHTML property by using JavaScript by simply assigning the property to a different value.

For example, imagine you have the following HTML tag:

 You can replace the content of 
tag by first retrieving the element using its identifier. Since the element 
has an id attribute with the value of greeting , you can use document.getElementById method to retrieve it and change its innerHTML property.

The content of 
tag will be changed as follows:

Knowing this, you can simply wrap the space where you want your JavaScript variable to be displayed with a element as follows:

The code above will output the following HTML:

And that’s how you can display JavaScript variable values using innerHTML property.

Display JavaScript variable using window.alert() method

The window.alert() method allows you to launch a dialog box at the front of your HTML page. For example, when you try running the following HTML page:

The following dialog box should appear in your browser:

The implementation for each browser will slightly vary, but they all work the same. Knowing this, you can easily use the dialog box to display the value of a JavaScript variable. Simply pass the variable name to the alert() method as follows:

 The code above will launch a dialog box that displays the value of the name variable.

Conclusion

Displaying JavaScript variables in HTML pages is a common task for web developers. Modern browsers allow you to manipulate the HTML content by calling on exposed JavaScript API methods.

The most common way to display the value of a JavaScript variable is by manipulating the innerHTML property value, but when testing your variables, you can also use either document.write() or window.alert() methods. You are free to use the method that suits you best.

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: The Variable element

The HTML element represents the name of a variable in a mathematical expression or a programming context. It’s typically presented using an italicized version of the current typeface, although that behavior is browser-dependent.

Try it

Attributes

This element only includes the global attributes.

Usage notes

Related elements

Other elements that are used in contexts in which is commonly used include:

If you encounter code that is mistakenly using for style purposes rather than semantic purposes, you should either use a with appropriate CSS or, an appropriate semantic element among the following:

Default style

Most browsers apply font-style to «italic» when rendering . This can be overridden in CSS, like this:

Examples

Basic example

Here’s a simple example, using to denote variable names in a mathematical equation.

p>A simple equation: var>xvar> = var>yvar> + 2p> 

Result

Overriding the default style

Using CSS, you can override the default style for the element. In this example, variable names are rendered using bold Courier if it’s available, otherwise it falls back to the default monospace font.

CSS

var  font: bold 15px "Courier", "Courier New", monospace; > 

HTML

p> The variables var>minSpeedvar> and var>maxSpeedvar> control the minimum and maximum speed of the apparatus in revolutions per minute (RPM). p> 

This HTML uses to enclose the names of two variables.

Result

Technical summary

Content categories	Flow content, phrasing content, palpable content.
Permitted content	Phrasing content.
Tag omission	None, both the starting and ending tag are mandatory.
Permitted parents	Any element that accepts phrasing content.
Implicit ARIA role	No corresponding role
Permitted ARIA roles	Any
DOM interface	HTMLElement

Specifications

Browser compatibility

BCD tables only load in the browser

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How to Use Javascript Variable in HTML

You can only use Javascript variable in HTML by linking the Javascript variable to a HTML element using an id or class attribute.

Linking Javascript Variable to HTML Element

Assign an id to the element.

 id="content-holder">Content is loading . 

If you check this now all you will see is:

You can now add Javascript to your page using script tags.

 // Write your Javascript code inside here  

Now, you can start working on the Javascript. Create your Javascript Variable.

var newContent = "This content will be loaded as a paragraph on the p tag when we add it through Javascript."; 

You grab the element in Javascript using the assigned id value.

var contentHolder = document.getElementById('content-holder'); 

To display the variable in HTML, assign the variable to the element in Javascript using the innerHTML property.

contentHolder.innerHTML = newContent; 

Complete Code

 id="content-holder">Content is loading . // Write your Javascript code inside here var newContent = "This content will be loaded as a paragraph on the p tag when we add it through Javascript."; var contentHolder = document.getElementById('content-holder'); contentHolder.innerHTML = newContent;  

You can use the above method for string and number variables.

Using Javascript Array Variable in HTML

To view array and object variables in HTML, you have to loop through the items in Javascript before passing them to HTML.

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4 Ways To Display PHP Variables in HTML (Simple Examples)

Welcome to a beginner’s tutorial on how to display PHP variables in HTML. So you have some PHP variables that you want to “insert” into an HTML element?

1. Use delimiters to weave between PHP and HTML –
2. Use the PHP short tag –
3. For multiple variables, we can echo an entire string of HTML.
   • echo «»;
   • echo «

     —

     «;

4. Alternatively, we can do a formatted print – printf(«

   %s

   «, $VAR);

That shall cover the basics, but let us walk through more examples in this guide – Read on!

TLDR – QUICK SLIDES

TABLE OF CONTENTS

DISPLAYING PHP VARIABLES

All right, let us now get started with the example of displaying PHP variables in HTML.

EXAMPLE 1) USING PHP DELIMITERS

Ever since day 1 of learning PHP, we have been taught to “start a PHP script with “. That is correct, but more accurately – “PHP will only process the parts enclosed in , the rest will output as-it-is”. So yes, at any point, we just “switch” into

EXAMPLE 2) PHP SHORT TAGS

It is a real hassle to be switching between PHP and HTML using the delimiter all the time, so just use the “shorthand” to quickly output a single variable.

EXAMPLE 3) ECHO HTML STRING

$first $second
"; // (B) DUMMY ARRAY $person = [ "name" => "Jon Doe", "email" => "jon@doe.com" ]; // (C) THIS WILL NOT WORK! // echo "
$person["name"] - $person["email"]"; // (D) WRAP VARIABLES IN CURLY BRACES echo "
 - ";

This should be self-explanatory… Things can get pretty ugly when you have multiple variables to output. So the smarter way is to just echo the entire string of HTML, with the variables “embedded” inside.

EXAMPLE 4) FORMATTED PRINT

 "Jon Doe", "email" => "jon@doe.com" ]; // (B) FORMATTED PRINT foreach ($person as $k=>$v) < printf("
%s: %s
", $k, $v); > // (C) THE USEFUL PARTS. $val = 123.45678; printf("
ROUND OFF 2 DECIMAL PLACES %0.2f
", $val); $val = 0.432; printf("
PAD UP TO 5 ZEROS, 2 DECIMAL PLACES %08.2f
", $val); $val = "123"; printf("
PAD WITH DOTS %'.10d
", $val); 

At first sight, the printf() function may just seem like a roundabout and confusing way of doing echo . But take some time to run through the reference manual (links below), it provides a lot of ways to format the string to your liking – Padding with numbers, alphabets, restricting decimal places, alignment, and a lot more.

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LINKS & REFERENCES

TUTORIAL VIDEO

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THE END

Thank you for reading, and we have come to the end of this guide. I hope that it has helped you with your project, and if you want to share anything with this guide, please feel free to comment below. Good luck and happy coding!

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