Capitalize the first letter (JavaScript)

Capitalizing the first letter of a string by means of JavaScript. Two variants, using the methods:

1. slice() + toUpperCase()
2. replace() + toUpperCase()

1. slice() + toUpperCase()

HTML code:

<div class="example">
	<p lang="en">capitalize the first letter</p>
	<p lang="ru">сделать первую букву заглавной</p>
</div>

JavaScript code:

<script>
var paragraphs = document.querySelectorAll('.example p');
var text = '';

for ( var paragraph of paragraphs ) {
	text = paragraph.textContent;
	paragraph.textContent = text[0].toUpperCase() + text.slice(1);
}
</script>

2. replace() + toUpperCase()

HTML code:

<div class="example example2">
	<p lang="en">capitalize the first letter</p>
	<p lang="ru">сделать первую букву заглавной</p>
</div>

JavaScript code:

<script>
var paragraphs = document.querySelectorAll('.example2 p');
var text = '';

for ( var paragraph of paragraphs ) {
	text = paragraph.textContent;
	paragraph.textContent = text.replace( /^./, text[0].toUpperCase() );
}
</script>

Note

It works for most of the characters of most of the modern languages. But there may or will be problems with characters beyond the Basic Multilingual Plane (BMP) of Unicode, some digraphs or other language specific incompatibilities with the Latin upper-lower case characters conventions.

See the discussions on internationalization:

• "Uppercase" doesn't mean the same thing in every language using a given script
• A Solution That Works For All Unicode Characters

Browser support

Windows

Firefox 13.0+

Google Chrome 51.0+

Opera 38.0+

Linux

Firefox 13.0+

Google Chrome 51.0+

Opera 38.0+

More

• Add thousands separator into numbers (JavaScript)
• Removing the last character from a string in Javascript
• Transliterating Russian to English in JavaScript
• Wrap each character of a string in <span> tag (JavaScript)