How to write an program for Tag a person like Fb,linkedin

It is just a auto complete text box. As you type, Your code should read the text in the textbox, send it to some server page/api endpoints with this text and other relevant information needed. The server page will query your db table and return your friends name in a list to the caller and you need to display it in a list under the text box. See this discussion: https://stackoverflow.com/questions/4564378/jquery-autocomplete-plugin-that-triggers-after-token