Using inline frames (iframe elements) to embed documents into HTML documents -: Using inline frames ( iframe elements) to embed documents into HTML documents An inline frame is a construct which embeds a document into an HTML document so that embedded data is displayed inside a subwindow of the browser's window. This does not mean full inclusion; the two documents are independent, and both them are treated as complete documents, instead of treating one as part of the other. Support to inline frames is not universal, but with a properly designed 'graceful degradation', they can be used in authoring for the World Wide Web. However, there are serious problems with printing documents containing them. This document also discusses the legal side of the matter as well as the details of the iframe element as defined in the HTML specifications, on one hand, and as implemented on IE, on the other. Content: Basically, an iframe element is of the form alternative content for browsers which do not support iframe display the document referred to by the URL in a subwindow, typically with vertical and/or horizontal scroll bars; such browsers ignore the content of the iframe element (i.e. Everything between the start tag and the end tag ).
Browsers which do not support iframe (or have such support disabled) do the opposite: process the content as if the and tags were not there. Thus, the content matters, despite being ignored by some browsers. See below for.
As a simple example, consider the following situation. We have a site which contains a separately updated newsflashes page, say. We would like to embed that page into some other page(s) so that the first few lines of its content are directly visible and the rest of it can be viewed by vertical scrolling. This could be written in HTML as follows: See our newsflashes. Inline frames do not mean an 'include feature', although it might sometimes serve similar purposes. The issue of including a document into another is discussed in question in 's.
Note that when inline frames are used, the browser (if it supports them) sends a request to the server referred to by the URL in the iframe element, and after getting the requested document displays it inside an inline frame. In this sense inline frames are a joint browser-server issue, but only the browser needs to be specifically iframe-aware; from the server's point of view, there's just a normal HTTP request for a document, and it sends the document without having (or needing) any idea on what the browser is going to do with it. (This answers the question 'Can I prevent others from inline framing my documents?' There is no effective technical method; but see below.), an iframe element is a text-level element, or (as opposite to block-level elements). Syntactically an iframe element may occur inside a paragraph, even between two words of text, though that's not particularly useful.
It may also occur e.g. Inside a table cell (though with ). Being text level, iframe does not imply line break before or after. Therefore, consider puting an iframe element inside a paragraph of its own (. ) or at least use before and after it.
Although browsers supporting inline frames ignore the content of the element, an iframe element needs some content and the closing tag. (If you omit the end tag, everything up to the end of the document will be taken as the content of iframe, i.e. Ignored by browsers supporting iframe!) The content can be empty, though, but only if such content really is an adequate replacement for the inline frame (in situations where the inline frame is not displayed). This is the case if the text of the document otherwise provides a surrogate for it, e.g. When a link to the embedded document appears in an introductory paragraph.
Typically the content should be either a link to the embedded document or a copy of the content of its body. In the latter case, the copy must not include the head part ( title etc.) or body tags, just the part that is inside the body element in the full document.
Some suitable authoring tools or server side mechanisms could be used to make the copying automatic. It might be useful to apply an approach that I call: Design the page first using simple and robust constructs, like very basic HTML elements that are universally supported. Then consider 'augmenting' it by offering some enhancements as alternatives which replace a simpler construct in some browsing situations. For example, write first a simple link to a document; later consider augmenting it e.g.
By slapping suitable iframe markup around it, so that iframe-enabled browsers will show that document an inline frame instead of displaying the link. As a special case, you might consider using the Netscape-specific element as the content. Note that although that element has some resemblance to iframe, it is fundamentally different. In particular, the entire document (referred to by the src attribute of the ilayer element) is displayed as a whole, not within any scrollable box.
Thus, this approach is probably suitable for small documents only. You still need to take into account that there are browsers which do not support either iframe or ilayer, so you need a content for ilayer, as the ultimate fallback. (Such browsers include Netscape 3 as well as most other browsers than Netscape and IE.) Example (with the rendering on your current browser below it): See our newsflashes. See our newsflashes.
The content of an iframe element can be just text, or it can contain text-level (inline) markup, or even block-level markup (such as the p markup for a paragraph above). The iframe element itself is technically an 'inline' element. You might find this somewhat confusing but it means that you can put both text-level and block-level markup around an iframe. On the other hand, Nick Theodorakis has reported, in and, that Mac IE5 shows both the inline frame and the alternate content, if you have p markup both inside the iframe element and outside it: yada yada. And that the problem is removed if you change the outer p markup to div markup.
Nick recommends that if authors use div markup rather than p as a block-level container for iframe, if they don't want the alternate content to be displayed by Mac IE5. Is partly obscure and does not say very explicitly what the effect of a src attribute really is, but it seems that if it is present, the content of the element is ignored, i.e. Only the content of the external file is displayed. And this is quite nice since it gives you the opportunity to provide a 'graceful degradation'.
It's an interesting question is what happens if and when Netscape drops layer support. This may well mean that future versions support iframe but not ilayer. In fact, it has been announced that. This should not be a problem if you have nested iframe and ilayer (either way) but it would be problem if you have them in succession.
Browser to the iframe element is not very wide yet, but increasing:. Internet Explorer has supported iframe since version 3. However, IE as well other browsers have in the support, as discussed later in this document. Netscape 6 supports iframe. It has been reported that Netscape 4.7 on Mac has iframe support, but all Netscape 4.
X versions on Windows probably lack support. And that M12 supports iframe.
supports it, with a user option to disable the support., but the 'small bugs' include failure to comply with the fundamental idea of. 2.8.2 handles iframe in a manner similar to its treatment of normal frames: it provides a link (preceded by the text IFRAME:) to the document specified in the src attribute of the iframe tag and then renders the content of the iframe element. As the link text, it uses the name attribute if present, otherwise the URL (the src attribute value). 4.0 beta supports iframe, with the option to turn the support off (as independently of normal frame support), and the default setting seems to be to have the support disabled. Browsers which do not support iframe are expected to ignore the start and end tags of the element and render its content instead.
This is a special case of the general idea of ignoring unknown tags. This could fail if a browser does recognize iframe but has a fundamentally incorrect implementation for it.
Luckily there don't seem to be such cases. Normal frames are used to divide the entire browser window (or a frame) to subwindows.
Inline frames appear inside the presentation of a document much the same way as images are: the browser allocates some space for an inline frame and takes this into account when rendering the document. This means, in particular, that an inline frame as a whole scrolls along with the rest of the document, so it might be scrolled away. Whether this is positive or negative depends on the aims and nature of the page. (An inline frame usually has its own internal scroll bar too, for scrolling its own content.) These features make inline frames an interesting possibility especially for embedding relatively small documents onto pages. On the other hand, as explained above, browser support to iframe is limited, more limited than for normal frames. On the other hand, normal frames are usually resizable by the user, though the author might manage to prevent this (using the noresize attribute). Inline frames are not resizable any more than e.g.
A table is, except in the sense that if the width or height is specified as a percentage, the actual width or height may change when the entire window is resized. If the user agent is not able to render the object for whatever reason (configured not to, lack of resources, wrong architecture, etc.), it must try to render its contents. And in fact, the object element is handled better than iframe by IE 4+: if the document specified in the data attribute is not available, the browser displays the content of the object element instead. On Internet Explorer (at least on version 5.0, Win98), there is an odd feature that is triggered when the src attribute contains a fragment identifier, i.e. The URL proper is followed by # location, e.g. Such a construct can be expected to position the document in the inline frame at the specified anchor location, similarly to the similar behavior with normal links.
P Block Elements Ppt
And this does happen on IE, but the browser also positions the enclosing document (i.e. The one containing the iframe element) there when it is first accessed. This can be very confusing. Printing inline frames seems to be rather problematic. To begin with, if there is a PDF document in an inline frame, printing the embedding document from IE seems to result in a failing attempt to print that PDF document only. (Tested with IE 4 on WinNT, using output to a PostScript printer, and with IE 5 on Win98, using a directly attached printer.
I get an empty paper with a URL of the PDF document at the bottom.) Moreover, when I print a document containing an HTML document in an inline frame positioned at an anchor, i.e. I have iframe src=' something.html# location, I get a print where the embedded document is positioned at the beginning, as if the part # location were not present. Yet another serious problem with printing is that inline frames with dimensions suggested via CSS get printed very oddly. It is as if the em unit got mapped to a small measure so that the inline frame is shrunk ridiculously. Perhaps this problem could be addressed by using separate style sheets for screen and print, but this would mean quite some extra effort. Interestingly, the printing problems were predicted as early as in 1996 in 's famous alertbox: Finally, it seems that the inline frames introduced in HTML 4.0 will be mostly harmless. A frame that is inlined will be subordinate to the main page, and the user can still bookmark the main page and navigate as usual.
Since mainstream browsers still do not implement HTML 4.0, we don't know whether inline frames will have their own implementation problems: in particular, it is doubtful whether good ways will be found to print pages that have scrolling inline frames (my current best guess is that it will be best to print the currently visible part of a scrolling inline frame in order to maintain the layout of the main page, but some users may want to have the entire contents printed, so messy option settings may be necessary). in the. in Microsoft's documentation of HTML as interpreted by Internet Explorer,.
P Block Elements Notes
in 's. in Brian Wilson's. in by Miko O'Sullivan. Greg Shultz, has written the review, which especially discusses the use of inline frames to replace normal frames. I don't think that's a good idea, but admittedly it might sometimes be an improvement over framesets with lots of frames just to to put a content frame in the midst of something.