javascript - JavaScript中如何判断变量的类型？

Question

我是 JavaScript 新手，正在使用 Netbeans 编写一个简单的网站。由于 JavaScript 是动态类型语言，我想知道在我不确定的情况下如何找出变量的类型。

例如，如何找出下面代码中emailAddress或domainPart的变量类型？

function getEmailAndDomainParts(){
                var emailAddress = document.getElementById("EmailAddress").value;
                var emailPart = emailAddress.substring(0, emailAddress.indexOf("@"));
                var domainPart = emailAddress.substring(emailAddress.indexOf("@") + 1);

                document.getElementById("Email").value = emailPart;
                document.getElementById("Domain").value = domainPart;
            }

Answer 1

// test data
var myArray = ['a', 'b', 'c'];

// the usual typeof isn't very useful
alert(typeof myArray);

// this instance of method tests the array
// to see if it is an instance of the 'Array'
// constructor, which it is!
alert(myArray instanceof Array)

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