Javascript Form with Auto-complete Search Function

Overview: To create a dynamic text field form that will search through an array of names and corresponding mobile numbers and display any partial matches in a drop-down list. Upon selecting an item from the list it will auto-complete the partially typed entry. The field will allow for multiple entries and can auto-complete for each additional entry. The functionality is similar to Google's Gmail or Yahoo Mail's compose fields. Only a HTML form with one text field, it’s functionality and simple UI of the drop-down field is to be designed. Case Functionality There will be two case functionalities for this form field. Case 1: The normal functionality will allow the user to choose items from the drop-down list as well as manually inputting other phone numbers into the field. Case 2: A special case where only the items from the drop-down list can be selected. The user cannot input any name or number that does not match what is available from the drop-down list. The functionality for both cases can be either be in separate scripts or a combined script. Technical Specifications: Names and mobile phone values will be stored within a Javascript array. No additional server functions are needed as this array will be dynamically generated. The items in the drop-down list can be selected by either by the choosing the item with a click of the mouse or by using the Up/Down arrow keys and pressing Enter/Return. The search field will allow for multiple entries and searches for each entry. Once the name/number has been selected, it will auto-complete the text field. The auto-completion will separate each entry with a comma and a space. (ie. David Smith , Janet Smith ) If the user moves the focus away from the field, any additional trailing commas will be removed. No validation is needed as it will be handled server-side. The script is to be coded in Javascript and will need be to cross-browser compatible. IE 5+ (PC only), Mozilla, ad Firefox. UI Design: The design of the drop-down should be designed with XHTML/CSS and allow for background-color and font formatting within the CSS. Only simple highlighting of the partially matched text and mouse over state needs to designed (See attached example).