IE11 TypeError

IE11 TypeError

I'm doing calcualtions with jquery and all works well in firefox. In IE11 I get the following message, "TypeError: Object doesn't support property or method 'trunc'"

I'm using trunc to drop the decimals. What does IE11 need for trunc to work? Thanks.

  1. function calculate_net(loan_table){
        $(loan_table + " input[name=net]").calc(
        // create the equation
        "(borrowed_v) - (lofa_v)",
        // define the variables used in the equation
        {
            borrowed_v: $(loan_table + " input[name=borrowed]"),
            lofa_v: $(loan_table + " input[name=lofa]")
        },
       
        function (s){
            if (isNaN(s)){
                return "0";
            } else {
                return Math.trunc(s);
            }
        }
        );
    }