Test if a character is UTF8

[jdc44]

Greetings all
Does PHP have a function to test if a character is UTF8?

I have a form and a user enters some text. I have no idea what character set the user is using, so on my end I wish to test the characters entered to see if they are or are not UTF8.

My page is using:
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

My form is using:
<form ... accept-charset="utf-8">

Yet still some people are entering characters that are giving me grief. One example is a zip code that has a lowercase a with a carrot above it. If it will show in this post it is this: ( 10010â ).

Entity number: &#226;

Entity name: &acirc;

Thanks,

[sneakyimp]

UTF-8 encodings are identical to ASCII encodings for some chars -- like plain old A-Z or 0-9 and some punctuation.

Why do you need to know the difference? Why can't you assume that all input is in fact UTF-8 encoded? When you say these chars are 'giving you grief', it may be that you neglect to assume utf-8 encoding in some stage of your processing.

I'm not certain, but as best I can tell this is how it's working:

• Your page says "this content is encoded as UTF-8". That tells the visitor's browser how to display your page properly.
• Your form says "all text entered is assumed to be UTF-8". This means that when a user types something in, their browser should probably know that content entered is utf-8.

Somewhere between the visitor hitting submit and your output (where your 'grief' appears) you might be improperly handling something. For instance, your database might not be using utf-8 as your charset. Or if you send the form info through email, the destination browser may not know that the content is utf-8 encoded.