Question

I need to take value from beginning of input to cursor. val() return whole string. How can I only this part which I`m interested in?

Answer 1

You can use selectionStart to get the caret position, so:

var caretpos = $('input').prop('selectionStart');
var value = $('input').val().substring(0, caretpos);

http://jsfiddle.net/Zzkaw/

Actually, as the name implies, selectionStart is used for selections. However, if there is no selection, selectionStart === selectionEnd, and the values represent the caret position.