Discount function of TextMate

purchase.js

pluralise_licenses: function() {
    var qty = Math.abs($("input_quantity").value);
    if (qty == 1) {
        $("license_pluralism").innerHTML = 'license (' + this.price(39) + ')'
    } else if (qty > 1) {
        var discount = 0;
        	if	(qty >= 15)	{ discount = 30 }
		else if (qty >= 10)	{ discount = 25 }
		else if (qty >= 4)	{ discount = 20 }
        var eur = Math.round(qty * 39 * (100 - discount) / 100);
        $("license_pluralism").innerHTML = 'licenses (' + this.price(eur) + ')'
    }
}