JavaScript If/Else

Question

我想知道如何讓我的JavaScript顯示經理薪水的不同結果。我有2個If語句，但它只顯示2個條件之一。

numberOfHoursWorked = parseFloat(numberOfHoursWorked); 
basePayRate = parseFloat(basePayRate); 

if (jobCategorySelectedIndex == 1) { 
    txtnumberOfHoursWorked = 50; 
    hourlyPayRate = 20; 
    jobCategorySelectedIndex = 1; 
    hoursEligibleForBasePay = 40; 
} 

else (jobCategorySelectedIndex == 1); { 
    txtnumberOfHoursWorked = 10; 
    hourlyPayRate = 20; 
    jobCategorySelectedIndex = 1; 
    hoursEligibleForBasePay = 10; 
} 

Answer 1

這是一般結構：

if (condition) { 
    // do this if condition is true 
} else { 
    // do this if condition is false 
} 

直接沒有條件else因爲如果if條件爲假，只有得到執行。或者，你可以這樣做：

if (condition) { 
    // do this if condition is true 
} else if (condition) { 
    // do this if first condition is false and this condition is true 
} else { 
    // do this if first and 2nd condition are both false 
} 

但即使你沒有這個（改變你的例子有點）

numberOfHoursWorked = parseFloat(numberOfHoursWorked); 
    basePayRate = parseFloat(basePayRate); 

    if (jobCategorySelectedIndex == 1) { 
     txtnumberOfHoursWorked = 50; 
     hourlyPayRate = 20; 
     jobCategorySelectedIndex = 1; 
     hoursEligibleForBasePay = 40; 
    } 
    else if (jobCategorySelectedIndex == 1) { 
     txtnumberOfHoursWorked = 10; 
     hourlyPayRate = 20; 
     jobCategorySelectedIndex = 1; 
     hoursEligibleForBasePay = 10; 
    } 

這是沒有意義的，因爲這兩個條件都是一樣的東西。第一個會觸發，第二個不會觸發，否則兩者都不會觸發。

那麼你這個評論：

當我改變了第二個條件從別的如果，它仍然只是 顯示第二如果txtnumberOfHoursWorked = 10

好了的聲明，所以現在你有這個：

numberOfHoursWorked = parseFloat(numberOfHoursWorked); 
    basePayRate = parseFloat(basePayRate); 

    if (jobCategorySelectedIndex == 1) { 
     txtnumberOfHoursWorked = 50; 
     hourlyPayRate = 20; 
     jobCategorySelectedIndex = 1; 
     hoursEligibleForBasePay = 40; 
    } 
    if (jobCategorySelectedIndex == 1) { 
     txtnumberOfHoursWorked = 10; 
     hourlyPayRate = 20; 
     jobCategorySelectedIndex = 1; 
     hoursEligibleForBasePay = 10; 
    } 

這兩個條件ns完全一樣，所以它們都被執行。你有相同的變量被分配，但有差異值。所以第二個代碼塊中的代碼將覆蓋第一個代碼塊。看看你的兩個條件：它們是一樣的。

我在想也許這就是你想要的，但我不確定爲什麼你要在代碼塊中爲jobCategorySelectedIndex賦值。 ESP的第一個代碼塊，因爲它已經有了值1，爲了使條件爲真

numberOfHoursWorked = parseFloat(numberOfHoursWorked); 
    basePayRate = parseFloat(basePayRate); 

    if (jobCategorySelectedIndex == 1) { 
     txtnumberOfHoursWorked = 50; 
     hourlyPayRate = 20; 
     jobCategorySelectedIndex = 1; // <-- this is unecessary 
     hoursEligibleForBasePay = 40; 
    } else { // <-- this gets executed if jobCategorySelectedIndex does not equal 1 
     txtnumberOfHoursWorked = 10; 
     hourlyPayRate = 20; 
     jobCategorySelectedIndex = 1; // <-- are you sure you want to do this?? 
     hoursEligibleForBasePay = 10; 
    }