Question

可能重复：
  Check variable equality against a list of values
  Javascript if statement with multiple permissible conditions

我必须在下拉列表（ul）中点击253项（li）中的相同21个。

滚动我必须在500多个页面上为同一个列表执行此操作，我想我可以Javascript注入每个ul，循环并单击每个li恰好是21之一。好像我不能做像

这样的事情

 if(item[i] === ('aasdf'|'basdf'|'cwefw'|'asdfd'|'trehe'|'ferth'|'erthg'|'erthh'|'ierth'|'jeth'|'kerth'|'lerth'|'merth'|'psdfg'|'gregq'|'rsrgs'|'sress'|'srget'|'sergu'|'sdfgsv'))

是否有一种语法更清晰的方式来编写下面这个丑陋的if语句？

var item = document.getElementById('myDropdownList').getElementsByTagName('li');

for (i=0;i<item.length;i++){

    if(item[i].innerText === 'Argentina' | item[i].innerText === 'Australia' | item[i].innerText === 'Brazil' | item[i].innerText === 'Canada' | item[i].innerText === 'China' | item[i].innerText === 'Colombia' | item[i].innerText === 'France' | item[i].innerText === 'Germany' | item[i].innerText === 'Indonesia' | item[i].innerText === 'India' | item[i].innerText === 'Italy' | item[i].innerText === 'Japan' | item[i].innerText === 'Malaysia' | item[i].innerText === 'Mexico' | item[i].innerText === 'Philippines' | item[i].innerText === 'Russia' | item[i].innerText === 'South Africa' | item[i].innerText === 'Sweden' | item[i].innerText === 'Switzerland' | item[i].innerText === 'United Kingdom' | item[i].innerText === 'USA'){

    item[i].click();

    }

}

Answer 1

您可以使用变量和多重比较，但这仍然很长：

var text = item[i].innerText;
if (text === 'Argentina' | text === 'Australia' | text === 'Brazil' | text === 'Canada' | text === 'China' | text === 'Colombia' | text === 'France' | text === 'Germany' | text === 'Indonesia' | text === 'India' | text === 'Italy' | text === 'Japan' | text === 'Malaysia' | text === 'Mexico' | text === 'Philippines' | text === 'Russia' | text === 'South Africa' | text === 'Sweden' | text === 'Switzerland' | text === 'United Kingdom' | text === 'USA')

或者您可以使用数组并检查字符串是否包含在其中。

var matches = ['Argentina','Australia','Brazil','Canada','China','Colombia','France','Germany','Indonesia','India','Italy','Japan','Malaysia','Mexico','Philippines','Russia','South Africa','Sweden','Switzerland','United Kingdom','USA'];
if (~ matches.indexOf(item[i].innerText) …

然而，对于complicated != -1 comparison和旧版IE中缺少原生indexOf，人们倾向于使用正则表达式：

var regex = /Argentina|Australia|Brazil|Canada|China|Colombia|France|Germany|Indonesia|India|Italy|Japan|Malaysia|Mexico|Philippines|Russia|South Africa|Sweden|Switzerland|United Kingdom|USA/
if (regex.test(item[i].innerText)) …

Answer 2

var options = ['Argentina', 'Australia', 'Brazil', 'Canada', ...];
if (options.indexOf(item[i].innerText) !== -1){
  // item[i] was found in options
}

那样的东西？使用Array.indexOf（除非我误读了这个问题？在哪种情况下发表评论，我会尽力重新回答我的答案）

Javascript：使用OR操作数将SINGLE值与MULTIPLE值进行比较

2 个答案: