為什么我的 JavaScript 代碼算術方程出現 NaN 錯誤

Question

我正在嘗試為一項任務創建一個婚禮宴會桌計划器應用程序，但是我的“table”變量出現了 NaN 錯誤，而我的 return 語句中的“guests”變量卻沒有。 圖片是我在我的網站上看到的，下面是腳本代碼。 我正在使用帶有 JavaScript 的 HTML 語言。 謝謝你的幫助！

function distribGuests() {

  // Read the table value inputed by the user
     var text = document.getElementById('tablesInputBox').value;

  // Convert what the user typed from text into a number.
     var t = (text);

  // Read the guests value inputed by the user
     var text = document.getElementById('guestsInputBox').value;

  // Convert what the user typed from text into a number.
     var g = (text);

  // Formula for variable "a", the rounded down value of guests
     var a = Math.floor (g / t);

  // Formula for variable "b", the rounded up value of guests
     var b = Math.round (g / t); 

  // Formula for variable "x", the end result for the first set of table distributions
     var x = (g - b * t) / (a - b);

  // Formula for variable "y", the end result for the second set of table distrubutions
     var y = (t - x); 

  // Use string concatenation to produce statement for end result of wedding table distribution
     var message = "There will be "+ x +" tables with "+ b +" guests and "+ y +" tables with "+ a +" guests";

  // Display the message in the div that has the outputDiv
     document.getElementById('outputMessage').innerHTML = message;
}

Answer 1

括號不會將字符串轉換為數字。

  // Convert what the user typed from text into a number.
     var t = (text);

應該：

  // Convert what the user typed from text into a number.
     var t = +text;

您也可以使用parseInt(text) ，但+text對於您的用例實際上是相同的（稱為類型強制）。

（兩種方法的區別分析見這個問題）