Question

我有一个变量CampaignType，它的值是0.但是在警报（双星内）中它变为1.为什么这样？这是我的javascript代码段

      if (CampaignType != 2) 
      {
       if (CampaignType = '1') 
        {
            **alert(CampaignType);**
            var CampaignAmount = (SelValue * CampaignPrice) / 100;
            SelValue = SelValue - (CampaignAmount);

        }
        else if (CampaignType = '0')
        {
            SelValue = SelValue - CampaignPrice;

        }
    }

Answer 1

=是赋值运算符。

==是比较运算符。

===是身份运营商。

Take a look on how to compare in JavaScript!

您的代码应为：

if (CampaignType != 2) 
  {
   if (CampaignType == 1) 
    {
        alert(CampaignType);
        var CampaignAmount = (SelValue * CampaignPrice) / 100;
        SelValue = SelValue - (CampaignAmount);

    }
    else if (CampaignType == 0')
    {
        SelValue = SelValue - CampaignPrice;

    }
}

Answer 2

您将值1分配给CampaingType：

CampaignType = '1'

如果你想比较：

CampaignType == '1'

Answer 3

你要分配它，执行：

if (CampaignType == '1')

Answer 4

那是因为您没有评估，而是设置值

使用

if (CampaignType === '1') //if you also want to verify they are the same type

if (CampaignType == '1') //if you do not want to verify if they are the same type

javascript如果条件问题

4 个答案: