Archive for September, 2011

Using jQuery’s Data APIs

In the beginning (well, beginning with jQuery 1.2.3 in early 2008) there was the jQuery.data() API. It offers a way to associate JavaScript data — strings, numbers, or any object — with a DOM element. As long as you manipulate the DOM element with jQuery, the library ensures that when the DOM element goes away, the associated data goes away as well. This is especially important for older versions of IE that tend to leak memory when JavaScript data is mixed with DOM data.

Most jQuery code sets data values using the higher-level .data() API; for example, $("div").data("imaDiv", true) sets a boolean value on every div in the document. This API, in turn, calls down to jQuery.data() with each element to set the value. For completeness, there are also jQuery.removeData() and .removeData() to remove data elements, and jQuery.hasData() to determine if any data is currently set for an element.

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