/* Empty Attributes */
img[alt=""], area[alt=""], *[class=""], a[href=""], a[href="#"], *[id=""], *[title=""]
{ border: 5px dotted yellow !important; }

/* Proposed Deprecation Due To CSS */
body[background], table[background], td[background], th[background],
input[border], table[border]
table[cellpadding],
table[cellspacing],
object[codebase],
img[height], object[height], table[height],
a[name], form[name], img[name], object[name],
a[target], area[target],
td[valign], th[valign],
img[width], object[width], table[width]
{ border: 5px dotted orange !important; }

/* W3C HTML 4 Strict Deprecated Attributes - http://www.w3.org/TR/html401/index/attributes.html */
applet[align], caption[align], div[align], h1[align], h2[align], h3[align], h4[align], h5[align], h6[align], hr[align], iframe[align], img[align], input[align], legend[align], object[align], p[align], table[align],
body[alink],
applet[alt],
applet[archive],
body[background],
body[bgcolor], td[bgcolor], tr[bgcolor], table[bgcolor],
img[border], object[border],
br[clear],
applet[code],
applet[codebase],
basefont[color], font[color],
dir[compact], dl[compact], menu[compact], ol[compact], ul[compact],
basefont[face], font[face],
applet[height], td[height], th[height],
applet[hspace], img[hspace], object[hspace],
script[language],
body[link],
applet[name],
hr[noshade],
td[nowrap], th[nowrap],
applet[object],
isindex[prompt],
hr[size], font[size], basefont[size],
ol[start],
body[text],
li[type], ol[type], ul[type],
html[version],
body[vlink],
li[value],
applet[vspace], img[vspace], object[vspace], 
hr[width], td[width], th[width], applet[width], pre[width]
{ border: 5px dotted red !important; }

/* Non W3C Proprietary HTML Attributes - http://en.wikipedia.org/wiki/Non-standard_HTML_tags#Proprietary_HTML_attributes */
body[bgproperties],
*[bordercolor], *[bordercolordark], *[bordercolorlight],
body[topmargin], body[rightmargin], body[bottommargin], body[leftmargin],
table[frame]
{ border: 5px dotted magenta !important; }



/* Empty Elements */
/*span:empty,*/ /*div:empty,*/ li:empty, /*p:empty,*/ td:empty, th:empty 
{ border: 5px solid yellow !important; }

/* Proposed Deprecated Elements */
input[type="button"], input[type="reset"], input[type="submit"], tt, big, small
{ border: 5px solid orange !important; }

/* W3C HTML 4 Strict Deprecated Elements - http://www.w3.org/TR/html401/index/elements.html */
applet, basefont, center, dir, font, isindex, menu, s, strike, u,
listing, plaintext, xmp
{ border: 5px solid red !important; }

/* Non W3C Proprietary HTML Elements - http://en.wikipedia.org/wiki/Non-standard_HTML_tags */
audioscope, bgsound, blink, bq, comment, embed, fn, ilayer, /*image,*/ keygen, layer, limittext, marquee, multicol, nobr, noembed, nolayer, nosmartquotes, rt, ruby, server, sidebar, spacer, wbr, xml, blackface, shadow
{ border: 5px solid magenta !important }



/* XHTML 1.0 Strict Deprecated Attributes  - http://www.w3.org/TR/xhtml1/#h-4.10 - http://www.w3.org/TR/xhtml11/changes.html#a_changes */
a[name], applet[name], form[name], frame[name], iframe[name], img[name], map[name]
{ border: 5px dotted lime !important }

/* XHTML 1.0 Strict Prohibitions  http://www.w3.org/TR/xhtml1/#prohibitions */
a > a,
pre > img, pre > object, pre > big, pre > small, pre > sub, pre > sup,
button > input, button > select, button > textarea, button > label, button > button, button > form, button > fieldset, button > iframe, button > isindex,
label > label,
form > form
{ border: 5px solid lime !important }



/* Deprecated Classes From Old Website */
.toolbg, .ulnone, span.b, ul.list, .eleven, 
.lines, .wide, .select, table.form, form td.b, table .top,
.gallerypic, .iegallery, .pic, .image, .transparent,
.wht, .blk, .blue, .dkgray, .ltgray, .brown, .quote, .greyhover
{ border: 5px groove red !important; }

/* Dreprecated JavaScript From Old Website */
input[onfocus*="normal1px()"],
input[onfocus*="change1px()"]
{ border: 5px dashed red !important; }

/* 404 Pages */
a[href*="/designs/web/web1/"],
a[href*="/designs/web/web2/"],
a[href*="/designs/web/web3/"],
a[href*="/designs/aitp/aitp-fvtc/"],
a[href*="/designs/aitp/aitp/"],
a[href*="/forms/contact.asp"], 
a[href*="/forms/email.asp"]
{ border: 5px double red !important; }

http://www.nealgrosskopf.com/tech/thread.asp?pid=17

CSS Diagnostics allows web designers and developers to highlight invalid HTML using CSS selectors. Say goodbye to the font tag by highlighting it in a large obnoxious border. It also has the ability to highlight 404 pages, old CSS classes and old JavaScript function calls.

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