[SOLVED] Checking if text field has certain text if not alert?

[Jason28]

Hi it is me again   Could anyone please give me a working example of javascript that checks to see if a field contains certain text and if it doesn't it errors?  Kinda like preg_match() with php.  I have one field that is used to upload .mp3 files only so I would like javascript to check that field to see if it contains .mp3 and if not it errors before the user uploads it.  Thanks!

[Jason28]

Oh NM I found a working example finally

 

if (document.forms[0].song_hifi.value.lastIndexOf(".mp3")==-1)
{
   alert("Please upload only .mp3 extension file");
   return false;
}