包含中断的 'if' 语句中的错误(wrox ch 3 练习 4)

Question

试图弄清楚这个时间表函数...它不起作用，因为包含中断的 if 语句似乎存在问题。 任何帮助将不胜感激。

function writeTimesTable (startNumber, endNumber, multNumber) {
  for (;startNumber <= endNumber; startNumber++) {
    console.log(startNumber  + " * " + multNumber + " = " + startNumber * multNumber + "</br>")
  }
}
/* writeTimesTable(3,4,5) */
var timesTable;
while ( (timesTable = prompt("Enter the times table", -1)) != -1)
  while (isNaN(timesTable) == true) {
  timesTable = prompt(timesTable + "  is not a valid number, please retry", -1);
  };
  if (timesTable == -1) {
  break;
  };
  console.log("<br />The " + timesTable + " times table<br/>)");
  writeTimesTable(timesTable, 1, 12);

Answer 1

你没有在外循环中使用括号。 如果没有括号，则在循环中仅执行第一条语句。

while ( (timesTable = prompt("Enter the times table", -1)) != -1){
  while (isNaN(timesTable) == true) {
      timesTable = prompt(timesTable + "  is not a valid number, please retry", -1);
  }
  if (timesTable == -1) {
      break;
  }
}