The param element may be nested within an applet or object element to pass parameters to the Java applet or object (typically, an ActiveX control in IE) as it is being loaded. Parameters provide ways for HTML authors to adjust settings of an applet or object without having to recode the applet or object. A parameter typically passes a name/value pair, which is assigned to the name and value attributes. You can have more than one param element per applet or object. The documentation for the applet or object should provide you with the information necessary to pass those parameter values.

Used with IE data binding to associate a remote data source column name with the parameter passed to a Java applet or object. In the following example, data from a data source's column named backColor is assigned to the value attribute, even though the attribute is not explicitly shown in the tag. More complex relationships are also possible with both object and applet elements. datafld works only with text file data sources in IE 5/Mac.

Used with IE data binding, this attribute advises the browser whether the source material arriving from the data source is to be treated as plain text or as tagged HTML. This attribute setting depends entirely on how the data source is constructed and what kind of data the param element is expecting. dataformatas works only with text file data sources in IE 5/Mac.

Used with IE data binding to specify the ID of the page's object element that loads the data source object for remote data access. Content from the data source is specified via the datafld attribute. datasrc works only with text file data sources in IE 5/Mac.

Assigns an identifier for the parameter that the applet or object is expecting. Parameters generally supply a name/value pair. An applet, for example, includes a routine that fetches each parameter by name and assigns the passed value to a variable within the applet. Documentation for the applet or object should provide a list of names and value types corresponding to the param elements.

When the valuetype attribute is set to "ref", the type attribute value advises the browser about the content type of the file referenced by the URL assigned to the value attribute. Omit the type attribute for other settings of the valuetype attribute.

The parameter value to be passed to an applet or object as the executable program or data loads. Parameter values are passed as string values, and it is up to the applet or object to perform the necessary internal coercion of the data to the desired data type. The value attribute is listed as optional because there may be instances in which the presence of the param element name attribute may be sufficient for the object. Once the applet or object loads its associated parameter values, scripts cannot dynamically modify those values unless the applet or object is scriptable and exposes methods designed to modify the values.

object element parameters can come in three flavors: data, object, and ref. The valuetype attribute uses these constants to tell the browser how to treat the value assigned to the value attribute for passing to the object. When the valuetype is data, the value attribute is passed as a plain text string. A valuetype of object means that the value attribute consists of an identifier (id attribute value) of some other object element defined earlier in the same document. The other object may be one whose declare attribute is set, and now the parameter values are being passed to instantiate the object. When valuetype is ref, the value attribute is a URL that points to a file or other resource where runtime values are stored (perhaps a set of parameter values).