17. A system for customizing behavior of a JavaScript widget on a web page, the system comprising: a computer readable storage medium comprising a code repository to store code for a web page, the code defining an implementation of a widget, and a processor configured to perform operations, the operations comprising: creating a HyperText Markup Language (HTML) Document Object Model (DOM) element; assigning a CSS class from the presentation definition language to the DOM element; obtaining a computed style for the DOM element, wherein the computed style is computed based on the CSS class assigned to the DOM element; extracting a CSS styling property from the computed style; parsing the CSS styling property to determine a widget-level option contained within the CSS styling property to be applied to the widget; and applying the widget-level option to the widget.
17. A system for customizing behavior of a JavaScript widget on a web page, the system comprising: a computer readable storage medium comprising a code repository to store code for a web page, the code defining an implementation of a widget, and a processor configured to perform operations, the operations comprising: creating a HyperText Markup Language (HTML) Document Object Model (DOM) element; assigning a CSS class from the presentation definition language to the DOM element; obtaining a computed style for the DOM element, wherein the computed style is computed based on the CSS class assigned to the DOM element; extracting a CSS styling property from the computed style; parsing the CSS styling property to determine a widget-level option contained within the CSS styling property to be applied to the widget; and applying the widget-level option to the widget. 18. The system of claim 17 , wherein the processor is configured to perform additional operations, comprising: checking a formatting validity of the styling property and the option, wherein the formatting validity is defined by a predefined standard in accordance with the widget; and implementing a default option within the widget in response to a determination that either the styling property or the option is invalid.