I am using the script below, which you advised me on, to add up the item totals on my webform.
One issue is that if a user deletes a number in an item field, it will not adjust the total until a new number is entered or a "0". Is there a way to change the script to recognize the deletion of a number as "0"?

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script> <script>var jQ = $.noConflict(true);
// version 1
jQ( document ).ready(function() {
// Set Total_Items_Entered2 to read only
jQ('input[name="Total_Items_Entered2"]').prop('readonly', true);
// add the class sum to all inputs that we want to add
jQ('input[name^="GB"]').addClass( "sum" );
// on keyup check that the value isn't blank and it's numeric
jQ('input[name^="GB"]').on('keyup', function() {

if (jQ(this).val()!="" || jQ.isNumeric(jQ(this).val())){
// if input value is good fire the function
calc_dues();
}
});

// This is the calculate function
function calc_dues() {

var sum = 0;

jQ('.sum').each(function(){

if(jQ.isNumeric(this.value)){

sum += parseFloat(this.value);

jQ('input[name="Total_Items_Entered2"]').val(sum);

}
});
}
});</script>

Drop the if statement.

awesome. thanks!

Thanks for that! another question.
In my previous version of webformbuilder, when i entered a "placeholder" in a field and made it readonly, the placeholder data would populate the database field. In this version it does not. Is there a way to change it so it does?

Will the input still be readonly?

Yes it will.

You should be able to add the value through jquery and your calculation script should clear it out if it's used.
Place this under your jQ(document).ready(function() {