jQuery变量范围超过函数调用？

Question

我有这个功能

function update_prices(product_selector){
    //kind of a hack to account for the sometimes having a professional price and sometimes not
    var price_count = product_selector.find('small.rt').length;
    for (i=0;i<=price_count;i++)
    {
        if(i == 0){
            var standard_selector = product_selector.find('small.rt:eq('+ i +')');
            var standard_price = standard_selector.attr('data');
        }
        if(i == 1){
            var business_selector = product_selector.find('small.rt:eq('+ i +')');
            var business_price = business_selector.attr('data');
        }
        if(i == 2){
            var professional_selector = product_selector.find('small.rt:eq('+ i +')');
            var professional_price = professional_selector.attr('data');
        }
    }
}

我有这个称之为的代码块

....
....
product_selector.find(".active_selector").removeClass('active_selector');
update_prices(product_selector);
....
....

standard_selector.text("something");
business_selector.text("something else");
professional_selector.text("another thing");

我的问题是我如何保留三个变量的范围,standard_selector business_selector并professional_selector在update_prices函数中创建

Answer 1

要在函数声明后保持这些变量持久化,您有以下选择:

1. 它们必须在更高级别范围内声明,并在您需要的持续时间内持续存在.
2. 它们需要是持续网页生命周期的全局变量.
3. 需要将它们指定为某个对象的属性,该对象持续所需的持续时间.这可以通过从函数返回具有这些值的对象或将对象传递到可以设置属性的函数中或通过具有放置属性的全局对象来完成.

最简单的解决方案(并不总是最好的)是通过在更高的范围内声明它们var并在函数中移除它们前面来使它们成为全局变量,这样您只需操作全局变量而不是使用局部变量:

// declare global variables in global scope
var standard_selector;
var business_selector;
var profession_selector;

function update_prices(product_selector){
    //kind of a hack to account for the sometimes having a professional price and sometimes not
    var price_count = product_selector.find('small.rt').length;
    for (i=0;i<=price_count;i++)
    {
        if(i == 0){
            standard_selector = product_selector.find('small.rt:eq('+ i +')');
            var standard_price = standard_selector.attr('data');
        }
        if(i == 1){
            business_selector = product_selector.find('small.rt:eq('+ i +')');
            var business_price = business_selector.attr('data');
        }
        if(i == 2){
            professional_selector = product_selector.find('small.rt:eq('+ i +')');
            var professional_price = professional_selector.attr('data');
        }
    }
}

或者,如果您只想从此函数返回它们,以便可以在范围内使用它们,则可以在对象中返回它们:

function update_prices(product_selector){
    //kind of a hack to account for the sometimes having a professional price and sometimes not
    var sel = {};
    var price_count = product_selector.find('small.rt').length;
    for (i=0;i<=price_count;i++)
    {
        if(i == 0){
            sel.standard_selector = product_selector.find('small.rt:eq('+ i +')');
            var standard_price = standard_selector.attr('data');
        }
        if(i == 1){
            sel.business_selector = product_selector.find('small.rt:eq('+ i +')');
            var business_price = business_selector.attr('data');
        }
        if(i == 2){
            sel.professional_selector = product_selector.find('small.rt:eq('+ i +')');
            var professional_price = professional_selector.attr('data');
        }
    }
    return(sel);
}

var selectors = update_prices(xxx);
// access selectors.standard_selector, selectors.business_selector, selectors.profession_selector here