callFunction7.js

var add = function(a, b) {
	if(typeof a !== 'number' || typeof b !== 'number') {
		throw {
			name : 'TypeError',
			message : 'add needs numbers'
		}
	}
	return a + b;
}
var try_it = function() {
	try {
		add("seven");
	} catch (e) {
		console.log(e.name + ' : ' + e.message);
		// TypeError : add needs numbers
	}
}
try_it();