data fetched from database and show a specific record for an user in table

Hi,
In my application two fields are the user id and user name,i want to show the user name and user id along with other details in a html table.
user id is a numeric dropdown menu and user name is text only.How can i show the specfic record in that table for that user which i have selected in both of the fields ,how i can fetch data from backend User table?am using html,css and javascript, Any suggestion would be grateful!Thanks..