0
我不明白這段代碼。while循環中聲明變量javascript
var timesTable;
while ((timesTable = prompt("Enter the times table", -1)) != -1) {.....}
爲什麼有必要先聲明變量?我試圖做到這一點:
while ((var timesTable = prompt("Enter the times table", -1)) != -1) {.....}
但它不起作用。有什麼問題?是關於範圍的東西?
完整的程序是:通過提前
function writeTimesTable(timesTable, timesByStart, timesByEnd) {
for (; timesByStart <= timesByEnd; timesByStart++) {
document.write(timesTable + " * " + timesByStart + " = " + timesByStart * timesTable + "<br />");
}
}
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);
}
document.write("<br />The " + timesTable + " times table<br />");
writeTimesTable(timesTable, 1, 12);
}
感謝。
定義的原因「不工作」。 – deceze