Convert JavaScript String to be all lower case?

Question

How can I convert a JavaScript string value to be in all lower case letters?

Example: "Your Name" to "your name".

Answer 1

Yes, any string in JavaScript has a toLowerCase() method that will return a new string that is the old string in all lower case. The old string will remain unchanged.

So, you can do something like:

"Foo".toLowerCase();
document.getElementById('myField').value.toLowerCase();

Answer 2

"Your Name".toLowerCase();

Answer 3

Use either toLowerCase or toLocaleLowerCase methods of the String object. The difference is that toLocaleLowerCase will take current locale of the user/host into account. As per § 15.5.4.17 of the ECMAScript Language Specification (ECMA-262), toLocaleLowerCase…

…works exactly the same as toLowerCase except that its result is intended to yield the correct result for the host environment’s current locale, rather than a locale-independent result. There will only be a difference in the few cases (such as Turkish) where the rules for that language conflict with the regular Unicode case mappings.

Example:

var lower = 'Your Name'.toLowerCase();

Also note that the toLowerCase and toLocaleLowerCase functions are implemented to work generically on any value type. Therefore you can invoke these functions even on non-String objects. Doing so will imply automatic conversion to a string value prior to changing the case of each character in the resulting string value. For example, you can apply toLowerCase directly on a date like this:

var lower = String.prototype.toLowerCase.apply(new Date());

and which is effectively equivalent to:

var lower = new Date().toString().toLowerCase();

The second form is generally preferred for its simplicity and readability, but the first has the benefit that it can work with a null value as well while the second requires a string. The result of applying toLowerCase or toLocaleLowerCase on null is null (and not an error condition). The first form may therefore come handy in some generic-handling code.

Answer 4

toLocaleUpperCase() or lower case functions don't behave like they should do. For example in Safari 4, Chrome 4 Beta, Firefox 3.5.x it converts strings with Turkish characters incorrectly. The browsers respond to navigator.language as "en-US", "tr", "en-US" respectively. But there is no way to get user's Accept-Lang setting in the browser as far as I could found. Only Chrome gives me tr although I have configured every browser as tr-TR locale preferred. I think these settings only affect HTTP header, but we can't access to these settings via JS. In the Mozilla documentation it says "The characters within a string are converted to ... while respecting the current locale. For most languages, this will return the same as ...". I think it's valid for Turkish, it doesn't differ it's configured as en or tr. In Turkish it should convert "DİNÇ" to "dinç" and "DINÇ" to "dınç" or vice-versa.

Answer 5

example

<script type="text/javascript">
var yourstring = 'Your Name'
var lowercase = yourstring.toLowerCase();
document.write('original string:<b> ' + yourstring + '</b><br>');
document.write('converted sting <b>' + lowercase + '</b>');
</script>

try it on

http://htmledit.squarefree.com/