FORMATTING LIMITATIONS
It's very difficult to display "boxes" of content.
Non-box type elements (like <SPAN>) do not justify contents into a box.
<DIV> auto-widths to 100% of available space in parent instead of to the
 runtime content of the DIV.
No box-type elements may be placed side-by-side, except by putting them
 inside of adjacent TABLE <TD>s.
Once you reduce width by specifying absolute width or using <TABLE>, there
 is still no general and portable way to specify hor. alignment.
 You can wrap a <CENTER> around it, or wrap a <TABLE width="100%"> around it.

INPUT HTML tags (called for Controls)
    <INPUT>, <TEXTAREA>, <SELECT>, <BUTTON>
title is an attribute usable for MOST HTML tags for a tooltip.
CSS text centering works for <INPUT>s, but not for <DIV>s.
Unfortunately, there is NO WAY to assign newlines in titles/tool-tips with FF.
IE uses line breaks exactly as you would expect and want!

Post stdin
Get on command-line.  Passed as value of $QUERY_STRING.

TABLE STYLING and Rules (internal borders)
** WARNING: See summary at bottom of this section.
CSS seems to override HTML attributes, except that there is no CSS
corresponding to cellspacing
TH and TD margin and spacing seem to have no effect
Unfortunately, can't duplicate table rules with CSS, since if set a border
 on cells, there would be a double border "between" cells but not around table.HHTML border att (NOT CSS!!!!) turns on table RULES="all" automatically.
To control rules as much as possible with CSS, specify 'rules="all"' in HTML
 but NO BORDER in HMTL.  Specify CSS style of "border:Xpx solid;".
 Without the "solid" part, only the internal borders get drawn with FF???
 X effects only the external border.  Internal borders only size 1???
 THIS TACTIC WORKS ONLY WITH FF
** Seems there is NO PORTABLE WAY to use styles to configure table rules.
** Just use td and table borders.  A consequence of this is, you must have
*  border width of a power of 2.

BROWN:  #884400

At least with FF 2.x, you must code the TABLE "cellspacing" attr if you
 want it 0 (or controlled by CSS).  The border and padding settings are
 overridden by CSS settings.


IFRAMES in IE 6.0 and Firefox  (It's "Inline Frames", not "Internal Frames").
The iframe file (*.html) is indeed a standalone HTML file.
Only a few styles of the parent document can effect the iframe document, so
the iframe file should generally load its own style settings.
The IFRAME tag is an INLINE not BLOCK element!

Main limitation of IFrames is, they cannot size automatically based
upon their content.  (Traditional frames can, by using "*" as COLS or ROWS
value).
BUT, the child can resize itself with JavaScript like so:
<BUTTON type='button'
    onclick='parent.document.getElementById("cif").height="200px";'>
    Resize Me</BUTTON>

If parent and child specify no size, you get fixed size of 300x150 px.
I.e., if you supply no width and height, you get
    width='300px' height='150px'
With fixed width and height, and auto scrolling (the default), you will
get scroll bars if there is more content in the IFrame than fits the w/h.

If you specify width or height in %, it sets the width and height of the
iframe to the % of the entire browser window (actually a little less).
If this size doesn't allow for the other content on the page, the 
browser will make scrollbars (not an iframe scrollbar as controlled by 
the 'scrolling' attribute).  If, for example, you set height to 100%,
you will need a scroll bar to see anything else on the page.

Seems you can't control horizontal and vertical scrollbars separately
for frames.  There is just one "scrolling" attribute.

INSIDE A TABLE
%ages >= 100%
    FFox: just leave the cell and iframe at default size of 300x150.
    IE:  Exactly as you would expect, sizing cell and IFrame, EXCEPT
      that the cell overwrites what is to the right (at least cells).
%ages < 100% leave the cell size at default size, but only draw the
   cell at the % size of 300x150
Pixel sizes 300x150 do exactly what you say, sizing cell and iframe.

Pulldown lists can't overlay another frame IN SOME SITUATION???
(They are working right for me right now, with both Iframes and Framesets).


FONT SETTINGS FOR PULLDOWN LISTS (i.e. <SELECT>s)
Setting for OPTION tag has no effect in I.E. 6.x; but effects display when
 "pulled down" in Firefox.
Setting for SELECT tag effects the unopened list box in Firefox (and default
 for "pulled down" list); and everything in IE.

IMPORTANT:  Some styles do not work right in IE6 until you add a DOCTYPE
tag to the file.  See http://htmlhelp.com/tools/validator/doctype.html


SIZING SETTINGS FOR IFRAMES
    Must set HTML WIDTH and HEIGHT atts.
    frameborder  (overridden by css border)
    Must set:     (CSS margin and padding settings are IGNORED!)
    marginwidth
    marginheight

favicon:  (This really is off-topic here, but I don't have an appropriate
file for this).
Need to put "favicon.ico" into app root directory.
Does not work to alias /favicon.ico, for unknown reason.
Good convert to .ico:  http://www.htmlkit.com/services/favicon/

Though HTML spec says that FORM "action" attr is required, in fact FF,
IE, Konqueror all submit forms to same URL by default.
At least with FF, get-method posts silently drop query string on the action.
Kinda funny that the params are preseved if method is post.

IE screws with radio button's "checked" attribute.  Specifically, clears
the value when it should not.


!!!!TERRIBLE IE BUG!!!!
IE inserts whitespace into displayed page if your HTML has white space after
<IMG> or <A><IMG></A> tags.  Likely happens with other tags or combinations too.

IE will add an extra blank line (or worse) if you have white space before <BR>.
Therefore DON'T EVER HAVE WHITESPACE BEFORE <BR> TAGS.

BUTTON should default to type "submit", but need to specify this type for IE6.


Funky characters:
http://eis.bris.ac.uk/~cckhrb/webdev/code/html/unicode.htm
http://en.wikipedia.org/wiki/List_of_Unicode_characters#See_also
Like:  &#9824; or &#x2660;


Good things about HTML standards and layout issues:
https://developer.mozilla.org/en/Mozilla_Web_Developer_FAQ

Definitely do close th and a tags!

Disabled vs. Readonly.  both are HTML 4.0.
They are decorated differently in IE at least.
READONLY  "ONLY" prevents entry of text.
DISABLED stops submittal, focus, etc.


P vs. DIV
P should only contain inline elements, whereas div may contain nearly anything.
As one example, P should not contain DIVs, but DIV may contain Ps.


Aria and role are HTML 5 attributes are handicapped people, etc.

Default 'types' for form elements.  INPUT defaults to "text", whereas
 BUTTON SHOULD default to "submit" but BUTTONs are seriously bugged in
 IE before v. 8.
 Always code non-submit/reset buttons as <button type="button"...
 FORM method defaults to get!
Not safe to use buttons for submit in IE < 8.  I suspect ok to use if
always specify type="button".  I don't know about type="reset".
Bind labels to form fields with either
    <label><input...>labelText</label>  OR
    <label for="idOfInputEl">labelText</label>
(depending on whether the element nesting agrees with where you want things
located).

HTML button/input elements do not serve their submit purpose in IE if
hidden.  (display:none).

BUTTON Gotcha:  MUST have separate open and close tags (I've read same for div).

See http://msdn.microsoft.com/en-us/library/ms537512%28VS.85%29.aspx#3
about "conditional HTML statements".
downlevel = Any browser (incl. version, that does not support conditional
 comments.  This includes IE < v. 5).
IE v.5 + only:
    <!--[if IE]> ... <![endif]-->
NON IE v.5+
    <![if !IE]> ... <![endif]>

There is no attr. for it, but HTMLElement.defaultValue for an input
element is the value that will be "reset to".

GOTCHA!
HTML forms STRIP get Params off of URL before sending ONLY IF METHOD IS POST!!

HTML IFrames
    Fortunately, both IE and FF honor CSS width+height over those attributes.
    For portability, always set 'frameboder="0"' (boolean), because with
    default of "1",
    IE always draws a thin border inside of any CSS borders (even if CSS
    border is set to 0).
    The scroll attributes has nothing to do with the size of the "containing
    page", but are for scrolling of the iframe contents within the iframe's
    width and height.  The 
    MUST SET WIDTH AND HEIGHT unless you want the default that is like
    200px x 80 px or so.
    marginwidth and marginheight attributes
        Apply to the CONTENTS of the iframe INSIDE BOTH BORDER TYPES, taking
        iframe bg color.
        Cf. iframe margin styles, which apply to the iframe OUTSIDE BOTH BORDER
        types and take the containing document's bg color.
        For HTML page content, far better to set the margin in that HTML, but
        for non-HTML may be useful.
        w3c apparently agrees with me on this, and suggests explicitly giving
        marginwidth="0" marginheight="0" for non-HTML iframes, to avoid
        IE bugs.

Most HTML elements DO NOT HAVE onload CALLBACK.  body and image tags do.

Per HTTP spec, forms always submitted with UTF-8 encoding.

Change default target frame:
<base target="_blank|_self|_parent|_top|<NAME>">   default is _self
Change default href target:
<base href="http://baba/path">
(Or both, of course)
https://www.w3schools.com/tags/att_base_target.asp

Make divs inline (setting display to inline does not work!):
div.inline { float: left; }

Javascript from HTML href attr values.
<a href='javascript:any code at all;'>