JavaScript
JavaScript is a cross-platform, object-oriented scripting language invented by Netscape. Its basis is Core JavaScript which can run both on the client (your browser, for example), and on the server. In addition, there are Client-side and Server-side JavaScript elements. All JavaScript source is integrated directly into HTML pages.
JavaScript is not class-based. Rather, it is an object-based language based on prototypes.
Core JavaScript
Core JavaScript includes the following elements:
- Keywords
- Statement syntax and grammar
- Rules for expressions, variables, and literals
- Underlying object model
- Predefined objects and functions, such as such as Array, Date, and Math
Client-side and Server-side JavaScript have different sets of predefined objects in the Underlying object model.
More Core JavaScriptClient-side JavaScript
More recent versions of clients or browsers (e.g. Navigator 2.0) can receive a page of HTML with JavaScript embedded in it. They read the page, displaying the HTML results and executing the JavaScript statements as it encounters them when reading from top to bottom. Embedded JavaScript statements can be used to respond to user events such as mouse clicks, form input, and page navigation, and can perform validation on the input.
JavaScript has evolved, so different versions of browsers deal with different versions and features.
Server-side JavaScript
JavaScript statements embedded into HTML on the server, which can include client-side JavaScript statements, can connect to a variety of relational databases, share information between users of an application, access the file system on the server, or communicate with other applications through LiveConnect and Java. Instead of each page being read as it is downloaded, however, they are compiled into bytecode executable files that are run by a web server that has the JavaScript runtime engine.
To create Server-side JavaScript, first HTML pages and JavaScript files are created, then these are all compiled into a single executable. When the client requests a page, the runtime engine finds the source page using the application executable, and dynamically generates it and returns it. The client runs any client-side JavaScript and displays the results.
You can use objects contained in Server-side JavaScript's Session Management Service to maintain data that persists across client requests, multiple clients, and multiple applications. An interface to Structured Query Language (SQL) database servers is provided by database access objects from Server-side JavaScript's LiveWire Database Service
Netscape provides a JavaScript debugger, with instructions.
There is a Netscape Visual JavaScript development tool for the Netscape Open Network Environment (ONE) platform.