假象回来假

Question

为什么if出现在第28和39行(这个javascript的if( clas == 1)和if( clas ==2 )总是错误的)？如果我用其他的代替第二个。每次都会被执行。我已经尝试过==和===，我也尝试将1和2作为字符串，同时使用和不使用clas = parseInt(cla)。

// JavaScript Document
var seat = new Array()
var fclass
var econ
var flight
var totseats

function init( seats, firclass, econo, flightnum )
{
    seat[0] = 'crew'
    fclass = firclass
    econ = econo
    flight = flightnum
    totseats = seats
    for( var count = 1; count <= seats; count++ )
    {
        seat[count] = 0;
    };
};

function reservation()
{
    var cla = document.getElementById('class').value;
    var name = document.getElementById('first').value;
    name += ' ';
    name += document.getElementById('last').value;
    clas = parseInt(cla)
    if( clas == 1 )
    {
        for( var seatnum = 1; seatnum < econ; seatnum++)
        {
            if( seat[seatnum] == 0 )
            {
                seat[seatnum] = name
                break;
            }
        }
    }
    if( clas == 2 )
    {
        for( var seatnum = econ; seatnum < totseats; seatnum++)
        {
            if( seat[seatnum] == 0 )
            {
                seat[seatnum] = name
                break;
            }
        }
    };
    pticket( name, seatnum );
};

function pticket( name, seatnum )
{
    document.getElementById('tname').innerHTML = name;
    document.getElementById('flight').innerHTML = 'Flight: ' + flight;
    document.getElementById('seat').innerHTML = seatnum;
    if( seatnum < econ )
    {
        document.getElementById('class').innerHTML = 'First Class';
    }
    else
    {
        document.getElementById('class').innerHTML = 'Economy';
    }
};

http://jsfiddle.net/FB26t/1/ p.s.jsfiddle根本不运行脚本，但它确实作为一个实际的网页正常运行

Answer 1

带有id类的元素不是您的<select>。怪不得。类<select>元素具有id选择。

此外，您还应该为radix函数指定parseInt参数，因为在所有浏览器中，缺省值不是10。

//and do not forget the var statement if you want a local variable
var clas = parseInt(cla, 10); 

小提琴

Answer 2

我已经放了document.getElementById('class').value，但是对应的元素实际上是document.getElementById('select')