- HTML scripting
HTML Series
The
W3C HTML standard includes support forclient-side scripting .It defines how locally executable scripts may be used in aweb page .A particular client-side application, such as aweb browser , may support several script languages.Script code may be executed as the document loads or at a later time.Script code can be written directly in the HTML document inside:
* SCRIPT elements
* Intrinsic event attributescript macros
The SCRIPT element type
SCRIPT elements may occur zero or more times within the HEAD and BODY elements. Scripts within script elements are processed as the document loads.
Intrinsic event attributes
Events occur for different elements of a web-page:
* Documents (BODY and FRAMESET)
* Forms
* UI elements (Anchor, Control Element, Image)Script code may be associated with an event and element by writing codein an HTML attribute.The name of the attribute must be that of a supported intrinsic eventfor the element (for example, "onLoad").The script is executed whenever the event occurs for that element.These scripts are mostly Javascript. The HTML intrinsic event model consist of the following events:
*Document
**onLoad
**onUnload
*Form
**onSubmit
**onReset
*Document and UI elements
**Focus
***onFocus
***onBlur
*UI elements
**Mouse
***Movement
****onMouseOver
****onMouseOut
****onMouseMove
***Button
****onClick
****onDblClick
****onMouseDown
****onMouseUp
**Keyboard
***onKeyPress
***onKeyDown
***onKeyUp
**Other (TEXT/TEXTAREA)
***Lost focus with modified content
****onChange (also OPTION)
***Text selection
****OnSelectSome browsers support additional event attributes (outside the standard), such as:
*onResize
*onMove
*onScroll
*onAbortScript macros
Netscape Navigator supported a feature called "JavaScript entities" or "script macros" by which script code could be included in HTML attribute values, using a syntax similar to that ofcharacter entity reference s. For example, the code<img width="&{prompt('Width?')};" src="foo.jpg">
calls the JavaScript prompt() function to ask the user how wide the image should be.The [http://www.w3.org/TR/REC-html40/appendix/notes.html#h-B.7.1 HTML 4.01 specification] reserves a syntax for the "future support of script macros" in HTML attributes, but they have not been incorporated into later standards and are not supported by any current browser.
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