jQuery 1.9.1, HTML, CSS, JavaScript
Mootools 1.4.5, HTML, CSS, JavaScript
jQuery 1.8.3, HTML, CSS, JavaScript
This fiddle shows how to use a regular expression to allow only English letters in an input field For the original post, go here: http://www.leniel.net/2012/10/javascript-regex-jquery-to-match-only-english-characters-in-input-textbox.html
jQuery 1.4.2, HTML, CSS, JavaScript
jQuery 1.7.2, HTML, CSS, JavaScript