HTML Entities / Attributes

Reserved characters in HTML must be replaced with character entities.

Characters that are not present on your keyboard can also be replaced by entities.

HTML Entities

Some characters are reserved in HTML.

If you use the less than (<) or greater than (>) signs in your text, the browser might mix them with tags.

Character entities are used to display reserved characters in HTML.

A character entity looks like this:

&entity_name;
OR
&#entity_number;

To display a less than sign (<) we must write: < or <

Advantage of using an entity name:An entity name is easy to remember.

Disadvantage of using an entity name:Browsers may not support all entity names, but the support for numbers is good.

Non-breaking Space

A common character entity used in HTML is the non-breaking space:  

A non-breaking space is a space that will not break into a new line.

Two words separated by a non-breaking space will stick together (not break into a new line). This is handy when breaking the words might be disruptive.

Examples:

• § 10
• 10 km/h
• 10 PM

Another common use of the non-breaking space is to prevent that browsers truncate spaces in HTML pages.

If you write 10 spaces in your text, the browser will remove 9 of them. To add real spaces to your text, you can use the   character entity.

The non-breaking hyphen (‑) lets you use a hyphen character (‑) that won't break.

Result	Description	Entity Name	Entity Number
``	non-breaking space	 	 
<	less than	&lt;	&#60;
>	greater than	&gt;	&#62;
&	ampersand	&	&#38;
"	double quotation mark	&quot;	&#34;
'	single quotation mark (apostrophe)	&apos;	&#39;
¢	cent	&cent;	&#162;
£	pound	&pound;	&#163;
¥	yen	&yen;	&#165;
€	euro	&euro;	&#8364;
©	copyright	&copy;	&#169;
®	registered trademark	&reg;	&#174;

A diacritical mark is a "glyph" added to a letter.

Some diacritical marks, like grave ( ̀) and acute ( ́) are called accents.

Diacritical marks can appear both above and below a letter, inside a letter, and between two letters.

Diacritical marks can be used in combination with alphanumeric characters, to produce a character that is not present in the character set (encoding) used in the page.

Here are some examples:

Mark	Character	Construct	Result
̀	a	à	à
́	a	á	á
̂	a	â	â
̃	a	ã	ã
̀	O	Ò	Ò
́	O	Ó	Ó
̂	O	Ô	Ô
̃	O	Õ	Õ

HTML Attributes

onchange

onchange="js_function(this)"

<script>
function js_function(obj) {
    console.log(obj.id)
    console.log(obj.value)

    obj.classList.add('custom-danger')
}
</script>