write the folowing click event
$('#trashico').click(function(){
$('.caption').text('What ever new name you want');
})
Update answer
As for what you try to achieve is sort of the windows F2 functionality. Try the following logic. You would have to implement it using the base idea I've given.
$('#trashico').click(function(){
$(this).addClass('active'); //Add a seperate class to identify on what is clicked
})
$(document).keyup(function(e){
if(e.keycode == 113 && $('.active').length > 0){
$('.caption').text('change name');
}
})
The above code will add a class to the clicked icon on your page. Sort of selected folder on windows. Then there is a keyup event bound to the document where it'll listen to what keys are pressed. when it hits 113 ( is the keycode for F2 ) then the if condition would be true and you would be able to change the name.
This is the basic logic of the OS renaming function. You would have to go through this base to achieve your requirement.