我正在尝试找出此Javascript代码出了什么问题

Question

function entertimesTable (timesTable,timesStart,timesEnd) 
{

    while (timesStart<=timesEnd)
    {

        document.write(timesTable + " * " + timesStart + "= " + timesTable*timesStart + "<br />");
        timesStart++;
    }
}

var timesTable;

    while ((timesTable=prompt("Please enter a table to use",-1) != -1)
    { 
        while (isNaN(timesTable) == true)
        {
            timesTable=prompt(timesTable + "is not a valid number, please retry", -1);
        }

        if (timesTable == -1)
        {
            break;
        }

        document.write("<br />The" + timesTable + " times table <br />");
        entertimesTable(timesTable,1,12);
    }

Its a simple function that does the times table for any number entered. A value of -1 will be invalid and I am also checking to make sure the user enter a valid number. It will not run. I have checked the syntax over and over again. This is my first question here.

Answer 1

You have an unmatched ( in your while statement:

while ((timesTable=prompt("Please enter a table to use",-1) != -1) //3 left parens and 2 right parens

Modify that line to read:

while ((timesTable=prompt("Please enter a table to use",-1)) != -1)