现代浏览器有 Array#includes，它完全和得到广泛支持 IE 除外:

Modern browsers have Array#includes, which does exactly that and is widely supported by everyone except IE:

console.log(['joe', 'jane', 'mary'].includes('jane')); //true

您也可以使用 Array#indexOf，它不太直接，但不需要为过时的浏览器提供 polyfill.

You can also use Array#indexOf, which is less direct, but doesn't require polyfills for outdated browsers.

console.log(['joe', 'jane', 'mary'].indexOf('jane') >= 0); //true

许多框架也提供了类似的方法:

Many frameworks also offer similar methods:

• jQuery:$.inArray(value, array, [fromIndex])
• Underscore.js:_.contains(array, value)(也别名为 _.include 和 _.includes)
• Dojo 工具包:dojo.indexOf(array, value, [fromIndex, findLast])
• 原型:array.indexOf(value)一个>
• MooTools:array.indexOf(value)
• MochiKit:findValue(array, value)
• MS Ajax:array.indexOf(value)代码>
• Ext:Ext.Array.contains(array, value)
• Lodash:_.includes(array, value, [from])(是 _.contains 之前的 4.0.0)
• Ramda:R.includes(value, array)莉>

• jQuery: $.inArray(value, array, [fromIndex])
• Underscore.js: _.contains(array, value) (also aliased as _.include and _.includes)
• Dojo Toolkit: dojo.indexOf(array, value, [fromIndex, findLast])
• Prototype: array.indexOf(value)
• MooTools: array.indexOf(value)
• MochiKit: findValue(array, value)
• MS Ajax: array.indexOf(value)
• Ext: Ext.Array.contains(array, value)
• Lodash: _.includes(array, value, [from]) (is _.contains prior 4.0.0)
• Ramda: R.includes(value, array)

请注意，一些框架将其实现为一个函数，而另一些框架则将该函数添加到数组原型中.

Notice that some frameworks implement this as a function, while others add the function to the array prototype.