Input mask rupiah

$('#pagu').inputmask({
        alias: 'numeric',
        autoGroup: true,
        groupSeparator: ',',
        rightAlign: false,
        digitsOptional: true,
        digits: 2,
        prefix: 'IDR ',
        allowMinus: true,
        autoUnmask: true,
        removeMaskOnSubmit: true
    });