Hi rani,
Difference between jquery autocomplete textbox and combobox are as follows:-
AutoComplete TextBox
AutoComplete textbox component is a textbox component that shows suggestion list based on the user query.
AutoComplete can be used in websites or webapplication where the user wants the list items to be filtered against the text typed in input area instead of browsing the complete list items for selection.
For example, sites with input boxes for searching available products in shopping sites etc.
ComboBox
ComboBox component is a combination of list box and DropDownList with editable text box and filtering functionality.
ComboBox can be used in websites where the users can either search their options in input box and the user can be able to edit the selected option via input box. This cannot be used in case of multiple selection.
It can be used in sites where the user can edit items in input box and enter an option that is not present in the predefined list of items.
