function runTotal(myForm) {

//code goes here

//declare variables

var form_field20  = Number(myForm.liability_first.value);

var form_field21 = Number(myForm.liability_second.value);

var form_field22 = Number(myForm.liability_third.value);

var form_field23 = Number(myForm.liability_fourth.value);

var form_field24  = Number(myForm.liability_fifth.value);

var form_field25 = Number(myForm.liability_sixth.value);

var form_field26 = Number(myForm.liability_seventh.value);

var form_field27 = Number(myForm.liability_eighth.value);

var form_field28 = Number(myForm.liability_ninth.value);

var form_field29 = Number(myForm.liability_tenth.value);

var form_field30 = Number(myForm.liability_eleventh.value);

//add the variables and update the total field value with the result.

myForm.total.value = form_field20 + form_field21 + form_field22 + form_field23 + form_field24 + form_field25 + form_field26 + form_field27 + form_field29 + form_field29 + form_field30;

}