What is a closure?
A closure is a function that has access to variables in the scope of another function .
The main function of closures
Answer: The scope of the variable is extended.
Closure application 1 (using the closure method to get the index number of the current small li)
Closure application 2 (calculate taxi price)
<script>
// 计算打车价格
// 打车起步价13（3公里内），之后每多一公里增加5块钱，用户输入公里数就可以计算
// 打车价格，如果有拥堵的情况，总价格多收取10块钱的拥堵费
var user_price = (function () {
var start = 13;
var total = 0;
return {
price: function (n, flag) {
if (n <= 3) {
total = start;
} else {
total = start + (n - 3) * 5;
}
if (flag == true) {
total = total + 10;
} else {
total = total;
}
return total;
}
}
})();
console.log(user_price.price(5, true));
console.log(user_price.price(1, false));
</script>