Document object model
?????? We open a web page, carry this web page is a browser, the browser exhibits web content to the viewer in the form of "Window"; this page is programmed From the perspective, it is a "Document" object. Not only that, the browser itself acts as a software (not a web page), its own status information, such as what resolution "screen", "screen", browser "(Navigator), not currently in the browser Retrofit index, some basic "local" information, etc. "Location" information such as page frame structure. These information, sometimes for web programming, but also need to let your web code know - Note: This information can be obtained through JavaScript code, but cannot control this information - for security, you can't pass you Web programming, control the client program (browser is a software of the client) running. ?????? Therefore, foreigners (especially foreigners using English) use English nouns as an object-oriented scripting language as "object" "" name. " According to the description of the above paragraph, there should be the following "object" name: Window, Navigator, Screen, History, Locationg, Document. Their level is as follows:
????? [window object]: The highest layer object, the object contains the area of the full HTML document content present in the browser window, in the multi-frame web environment, each frame is a Windows object, is an object Hierarchical group of other layers. ?????? [Navigator Object]: This object is an information on the browser program itself. For JavaScript code, this information is read-only (these information is read-only (to protect the browser program from illegal JavaScript code interference), these Information is used to read the browser's variety, version and other information, and keep the content information of the current browsing web page. ?????? [screen object]: read-only object, enabling the JavaScript code to get the physical environment where the browser is running (screen resolution, etc.). ?????? [History Object]: The sequential index and link of all historical pages in the browser recently, JavaScript cannot get the details inside the History, mainly used for page [Forward] / [Back] orientation. ?????? [location object]: Mainly provides different pages to the current window or framework, JavaScript cannot track access to other sites. ?????? [Document Object]: Load every HTML document object to the window, each documnent contains scripts, HTML elements. For example, each HTML page contains the most basic label elements. This object is the most enriched page effect and information.
