JavaScript is a literal-translation scripting language, which is a dynamic type, a weak type, a prototype-based language, and a built-in support type. Its interpreter, known as the JavaScript engine, is widely used as a scripting language for the client, and is used in HTML (an application under the standard Universal Markup Language) to add dynamic functionality to an HTML Web page. In 1995, the Brendan Eich of Netscape Company was first designed and implemented in Netscape Navigator's browser. Because Netscape is working with Sun, Netscape Management wants it to look like Java, so it's named JavaScript. But in fact its grammatical style is closer to self and scheme. [1] In order to gain technical advantage, Microsoft launched the Jscript,cenvi launch Scriptease, and JavaScript can also be run on the browser. For uniform specifications, JavaScript is also known as ECMAScript because it is compatible with the ECMA standard. The JavaScript technology architecture contains five aspects: JavaScript core language definition, native object and built-in object, browser object model BOM, Document Object model DOM, event handling model. There are five primitive types of javascript: Undefined, Null, Boolean, number, String. When declaring a variable uninitialized, the default value for the variable is Undefined.nan, which is a special value that is not a number. JavaScript is a weakly typed language and it is flexible. Defining a variable does not require declaring the data type, and the variable is not necessarily initialized.
Understanding Java Script
