The <object> element defines an embedded object. The <object> element is used to embed multimedia objects into web pages that are generally not natively supported by the browser. Object can be used for video clips, sound, images and other media formats. “Other media formats” include formats that are generally natively supported by browsers, such as images, text and html. The <object> element (and the various attributes) and child parameters provide browsers and multimedia application embedded in browsers with the information required to display multimedia objects.
<object data="myImage.png" type="image/png"></object> <object data="myIframe.html" type="text/html"></object> <object data="myMusicFile.mpeg" type="application/mpeg"></object>
Listing 1: the <object> element is a generic way of including media. Use more type specific elements, such as <img> or <iframe> when available. The <img> element is discussed in part 9 of this series.
The <object> element is generally used for embedding multimedia that requires the browser to load an external application to render the media (such as a flash movie or an audio file). The <object> element, along with its attributes and child <param> elements, allows you to specify everything required by the object — applets, plug-ins, media handlers and other components you may want to include in your web page — for presentation of that media by the browser and browser plugin, including source code, data type, initial values, etc. When including a Java applet, a .swf file, an ActiveX object, or other multimedia object, specify the data and parameters for objects and the code that can be used to display and manipulate the object data via <object> element attributes and child <param> elements.
Specifications and Browser Support
While the object element was supposed to be an important addition to the HTML 4.0 standard, it is still not completely supported by all browsers; though all browsers do support it to some extent. Whether an object is supported by the browser depends on the object type. The object element can be used to show many different media types such as ActiveX, PDF, Flash, or HTML, images and text files). Unfortunately, some browsers use different code to load the same object type. The nesting of the object elements is a great solution to enable you to degrade media based on browser support.
The <object> element can be located in either the <head> or as a child of the <body> element. The <object> can be found inside both block and inline elements, including inside the <button> and <a> elements, but NOT as a child of the <pre> element. The <object> element, in turn, can contain both inline and block level elements, including <param>, <form>, text and child object elements. While we’ll discuss <param> below, note that if a <param> element is found between the <object> and </object> it is part of the object of which it is a direct child and not an alternate code to execute. If text is found between the opening and closing <object> tags, it is alternate text for browsers that do not support the <object> element or the media defined by the <object> element. If the browser is able to display any of the parent media, then the text will not be displayed.
While the object element is an INLINE element, it can contain both inline and block level elements. Because it is an inline element, some recommend only including inline elements as children. If you are providing alternative content that will be displayed, my view is that you should use whatever HTML elements are most appropriate for displaying the default content, since it is valid to do so.
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,28,0" width="368" height="190" title="This is my flash movie"> <param name="movie" value="myFlash.swf" /> <param name="quality" value="high" /> <object data="myImageName.jpg" type="image/jpeg"> Some text </object> </object>
Listing 2: Example of code for an <object> element embedding a .swf file. I’ve added a nested image object for browsers not supporting flash (think iPhone!), and some default text if images are not displayed or found.
The <object> element
<object> elements can be nested inside a parent <object> element to provide the browser with alternative content to present if the browser is unable to display the media included by the outermost parent <object>. The browser walks thru the nested <object> media until it finds a media type it can render. If a browser is unable to render the media type of the parent object, the browser will try to render the next child <object> element until it finds an <object> with a datatype it is able to render. The search for the first renderable child will continue thru all the included object, and, if no renderable <objects> are found, the browser will display any HTML content, including images, that is the child of the inner-most <object> element.
For example, if you are displaying a Flash movie, but the user’s browser does not have the flash player installed, then you can present the user an image. However, if the user is using a tele-type reader, then you can serve the user text instead.
If the <object> element does not display properly, the content nested between the <object> and </object> tags will be executed. This allows allows you to have several nested object elements (one for each browser, depending on browser media support), and default text for some browsers if the content is not found or if the media is not supported.
Note: When the browser supports the media type, but the file is not found, browsers differ on whether or not to show the nested content.
Examples of simple <object> elements in action
<object data="real_file.htm" type="text/html" width="300" height="200"> <p>The link to <a href="missingfile.htm">a real page</a> will not show in browsers,since browsers can render html</p> </object>
EXAMPLE 1: Since the HTML data file DOES exist, the HTML file linked to with the data attribute will display. Browsers include the html file object in an iframe like display — in this case a 200 x 300px iframe since height and width were declared.
<object data="fake_file.htm" type="text/html" width="300" height="200"> <p>The link to <a href="missingfile.htm">a missing page</a> will show in some browsers, and not in others </p> </object>
EXAMPLE 2: Since the HTML data file does NOT exist, the above will display differently in different browsers. For example, IE6 provides an empty iFrame like 200px by 300px space, Safari displays the paragraph, and Firefox displays nothing.
<object data="real_pdf.pdf" type="application/pdf" width="300" height="200"> <p>The link to <a href="real_pdf.pdf>a real pdf file</a> will show in some browsers. Others will display the Adobe Acrobat application within and iframe</p> </object>
EXAMPLE 3: Since the pdf file DOES exist, the HTML file linked to with the data attribute will display IF the browser supports displaying PDF files within a browser window. However, if the user’s browser does not support in-browser displays of Adobe Acrobat, the paragraph with the link to the pdf file will be displayed.
<object data="myMusicFile.mpeg" type="application/mpeg"> <object data="missingImage.jpg" type="image/jpeg"> My Text Replacement </object> </object>
Listing 4: If you have Quicktime, or some other audio format plugin supported by your browser, the music file will be displayed. If there is no media player, the browser will display the JPG instead of MPEG. However, in our example, the image doesn’t exist. Firefox and Safari correctly display the replacement text. However, IE6 tries to display the missing image.
Note that in example four, the image is included as an <object> instead of <img> because I wanted to display the text ONLY if the image did not load: I didn’t want to display both. Browsers will consider the <img> element as part of the data to be displayed if the user agent can not render the data in the outer object element. Since the <object> element does not support the alt attribute, a better way of coding the contents of listing 2 would be:
<object data="myMusicFile.mpeg" type="application/mpeg"> <img src="myImageName.jpg" alt="My Text Replacement" /> </object>
This is more appropriate since you can include an alt attribute with the image. If a user agent does not render images, the text provided in the alt attribute will be displayed, which was what was intended in Listing 2.
Attributes of the <object> element
In addition to the core attributes and internationalization attributes, the <object> element accepts the following attributes:
The declare attribute, when included, states that the object should only be declared, not created or instantiated until needed. The declare attribute only takes one value:
The classid attribute defines a class ID value as set in the Windows Registry or a URL. Used to specify the location of the object’s implementation, the URL syntax depends upon the object’s type. The value can be either a traditional address or an apparently incomprehensible string of letters and digits that are actually the letters C-L-S-I-D, followed by a colon, space and the object ID, such as “CLSID: 99B42120-6EC7-11CF-A6C7-00AA00A47DD2”, for an ActiveX control. Classid is used in conjunction with or as an alternative to the data attribute. Unless you can figure out the Registry of classid’s, get the correct classid value from the supplier of the ActiveX control. For example, for .swf files, the classid value is generated by Flash when the developer publishes the .swf and associated .html file from the .fla file. Or, when using Dreamweaver to inset media, Dreamweaver automatically includes the correct classid value..
This codebase attribute contains the URL to use as a relative base for the URL specified by the classid attribute. In Listing 2 above, the URL of the codebase points to the codebase for the flash player or plug in. Note that the URL for the SWF file is included in the child parameter and NOT in the <object> element.
Another URL, the data attribute contains the location of the data required by an object. This should be either a relative or absolute path the your file.
This type attribute specifies the content-type, or MIME type, for the object’s data. This is different from the codetype (below), which is the MIME type of the object and not of the data it uses.
This attribute specifies an object’s content-type, or MIME type. This defines the MIME type of the object, not the the data the object may use, as defined in the data attribute.
This archive attribute contains an absolute or relative URL, or space separated list of URLs, for the location of archive files. An archive file is generally used to contain multiple object files to improve the ability to access the object improving perceived download time.
If you want to define the text displayed while the object is loading include the standby attribute with the text message to be displayed as the attribute value.
This height attribute specifies the height of the object in pixels or as a percentage of the enclosing window, depending on whether the percentage symbol is included. This value is overridden if the CSS defines a height for the object.
This width attribute specifies the width of the object in pixels or as a percentage of the enclosing window, depending on whether the percentage sign is included in the attribute value. The CSS width property overrides the element attribute value when included.
Objects can have hyperlinks associated with them through standard links using the <a> element, thru embedded linking mechanisms such as links in a flash movie, and also via image maps. The usemap attribute generally takes a fragment identifier referencing a map element somewhere else within the file of the image map to be used with the object as the value, but can also take an URL to a map in a separate file in browsers that support such behavior. If you include the usemap attribute, you should also include a <map> and the object will most likely be an image. An image map specifies active geometric regions of an included object and assigns a link to each region. Image maps are covered in part 10 of this series.
The name attribute is allowed, but is not required.
Along with <a>,<area>,<button><input>, <select> and <textarea>, the <object> element also supports the tabindex attribute.
The border, align, datafld, dataformats, datasrc, hspace and vspace attributes for the <object> element have all been deprecated in XHTML.
The <param> element
The <param> element is used to define special parameters used to control Shockwave and Flash SWF files, ActiveX controls, Netscape Navigator plug-ins, and Java applets. The <param> element can only be nested within a parent <object> or <applet> element. (Note that the <applet> element is not valid in XHTML strict). Parameters set attributes specific to different types of objects. For example, a Flash object can use a quality parameter <param name=”quality” value=”best”> for the object tag. If you are using Dreamweaver, you will find a Parameter dialog box in the Property inspector.
The <param> element is an empty element, so must be closed with a trailing slash. The name attribute is REQUIRED. The value attribute, while optional, should be included. The <param> element also accepts the id, valuetype, and type attributes.
Note: There is no widely accepted standard for identifying data files for ActiveX controls. See the documentation for the object you’re using for information on the parameters it requires.