無法在do while循環中結束提示框過程

Question

當用戶在提示框中輸入數字999時，我對於結束此Java腳本過程有個小問題，因爲不是這樣做，它只是將999作爲任何對待輸入其他號碼。 我該如何防止這種情況發生？謝謝。

<script> 
    var entry; 
    do { 
     entry = prompt("Enter degrees in Fahrenheit\n" + 
         "Or enter 999 to end entries", 999); 
     entry = parseInt(entry); 

     window.alert("Fahrenheit = " + entry + 
     "\nCelcius = " + ((entry - 32) * (5/9)) + " degrees"); 

    } while (entry != 999); 
</script> 

Answer 1

試試這個：

var entry; 
 
while (true) { 
 
     entry = prompt("Enter degrees in Fahrenheit\n" + "Or enter 999 to end entries", 999); 
 
    
 
    if (entry==999) { 
 
    break; 
 
    } 
 
    entry = parseInt(entry); 
 

 
    window.alert("Fahrenheit = " + entry + "\nCelcius = " + ((entry - 32) * (5/9)) + " degrees"); 
 

 
}