通過函數調用jQuery變量作用域？

Question

我有這個功能

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'); 
     } 
    } 
} 

，我有這個塊的代碼調用它

.... 
.... 
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"); 

我的問題是如何保持的範圍爲三個變量standard_selectorbusiness_selector和professional_selector是獲得創建在update_prices函數中

Answer 1

爲了讓這些變量在函數聲明後保持不變，您可以選擇這些選項：

1. 它們必須在更高級別的範圍內聲明，並在您需要的時間內持續存在。
2. 它們需要是全局變量，可以保存網頁的整個生命週期。
3. 需要將它們分配爲持續所需持續時間的某個對象的屬性。這可以通過從函數返回一個包含這些值的對象，或者將一個對象傳遞給可以設置屬性的函數，或者通過使用一個全局對象來放置這些屬性來完成。

最簡單的解決方案（認爲並不總是最好的），是在較高的範圍，宣佈他們，在他們面前的功能刪除了var所以你只是在全局變量操作，而不是讓他們的全局變量

// 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，如果你只是想從這個函數返回他們這樣你就可以在範圍內使用他們一個級別，那麼你可以在一個對象返回他們：

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 

Answer 2

使用局部變量

將它們作爲對象返回

function update_prices(product_selector){ 
    ... 
    return {standard_selector:standard_selector, business_selector:business_selector, professional_selector} 
} 

var r = update_prices(product_selector); 
r.standard_selector.text("something"); 
r.business_selector.text("something else"); 
r.professional_selector.text("another thing");