Find the input box that triggered the event

I have a html script with the following code

   <input type="text" name="" id="PrDisplay" onkeyup="calcCosting()"/></td>
   <input type="text" name="" id="PrFreight" onkeyup="calcCosting()"/></td>

I have many lines like this and when any input box has an entry then my JQ function is triggered

this is the Js code

function calcCosting() {

// calculate the sum of all the chargable items 
dis = $('#PrDisplay').val() /1   ;
fre = $('#PrFreight').val() /1 ;    
pro = $('#PrProcess').val()/1   ;   
str = $('#PrStructual').val() /1  ; 
gro = $('#PrGroundworks').val()/1 ; 
sof = $('#PrSoftware').val() /1 ;   
har = $('#PrHardware').val() /1 ;   
add = $('#PrAdditional').val() /1 ;

tot  = dis + fre + pro + str + gro + sof + har + add;
$('#PrTotal').val(tot) ; // display the total 
    }

This works fine and adds up all the totals to display them in a test box with the id PrTotal.

What I want to do in my JQ script is 开发者_如何学编程find the Text box that triggered the call to the script, or which box has focus as is call my script. I hope this makes sense !! , I really cant get to grips with the THIS element can somebody please give me some pointers ?

thanks in advance

---

you can simply use onkeyup="calcCosting(this)" in your code, and get that argument in calcCosting function.

Update:

Also you can bind the events to the <input> tags with JS/Jquery (instead of using HTML attributes) and easily access this object:

document.getElementById('PrDisplay').onkeyup=calcCosting;

---

You can try this instead, bind it and assign the function in jQuery all at once, like so:

$("input:text").bind("keyup", function () {
    // $(this) == current input (type=text) element

    // calculate the sum of all the chargable items 
    dis = $('#PrDisplay').val() /1   ;
    fre = $('#PrFreight').val() /1 ;    
    pro = $('#PrProcess').val()/1   ;   
    str = $('#PrStructual').val() /1  ; 
    gro = $('#PrGroundworks').val()/1 ; 
    sof = $('#PrSoftware').val() /1 ;   
    har = $('#PrHardware').val() /1 ;   
    add = $('#PrAdditional').val() /1 ;

    tot  = dis + fre + pro + str + gro + sof + har + add;
    $('#PrTotal').val(tot) ; // display the total 
});