Generated by SassMeister.com.

SassMeister-input-HTML.html

<div></div>

<br>

<a href="">link</a>

<br><br>

<strike>Don't use me anymore</strike>
<u>I'm deprecated</u>

<br>

SassMeister-input.scss

// ----
// Sass (v3.3.10)
// Compass (v1.0.0.alpha.20)
// ----

/* ==========================================================================
   Find and Highlight Mistakes in HTML
   ========================================================================== */
// Credit to Eric Meyer, and Chris Coyier
// for the article: 
// http://css-tricks.com/snippets/css/css-diagnostics/

// Add this variable to your global stylesheet
$find-mistakes: true;

// Then in a separate scss file (i.e. _mistakes.scss)

@if $find-mistakes {
/* ==========================
   Empty Elements
   ========================== */
  div, span, li, p, td, th {
    &:empty {
      padding: 2em;
      border: 2px dotted purple !important;
      background-color: lighten(purple, 50%);
    }
  }

/* ==========================
   Empty Attributes
   ========================== */
  *[alt=""],
  *[title=""],
  *[class=""],
  *[id=""],
  a[href=""],
  a[href="#"] {
    border: 2px solid blue !important;
  }

/* ==========================
   Deprecated Elements
   ========================== */
  applet,
  basefont,
  center,
  dir,
  font,
  isindex,
  menu,
  s,
  strike,
  u {
    border: 2px dotted red !important;
  }

/* ==========================
   Deprecated Attributes
   ========================== */
  *[background],
  *[bgcolor],
  *[clear],
  *[color],
  *[compact],
  *[noshade],
  *[nowrap],
  *[size],
  *[start],
  *[bottommargin],
  *[leftmargin],
  *[rightmargin],
  *[topmargin],
  *[marginheight],
  *[marginwidth],
  *[alink],
  *[link],
  *[text],
  *[vlink],
  *[align],
  *[valign],
  *[hspace],
  *[vspace],
  *[height],
  *[width],
  ul[type],
  ol[type],
  li[type] {
    border: 2px solid red !important;
  }

/* ==========================
   Proposed Deprecated Elements
   ========================== */
  input[type="button"],
  big,
  tt {
    border: 2px dotted green !important;
  }

/* ==========================
   Proposed Deprecated Attributes
   ========================== */
  *[border],
  a[target],
  table[cellpadding],
  table[cellspacing],
  *[name] {
    border: 2px solid green !important;
  }
}

SassMeister-output.css

/* ==========================================================================
   Find and Highlight Mistakes in HTML
   ========================================================================== */
/* ==========================
   Empty Elements
   ========================== */
div:empty, span:empty, li:empty, p:empty, td:empty, th:empty {
  padding: 2em;
  border: 2px dotted purple !important;
  background-color: #ff80ff;
}

/* ==========================
   Empty Attributes
   ========================== */
*[alt=""],
*[title=""],
*[class=""],
*[id=""],
a[href=""],
a[href="#"] {
  border: 2px solid blue !important;
}

/* ==========================
   Deprecated Elements
   ========================== */
applet,
basefont,
center,
dir,
font,
isindex,
menu,
s,
strike,
u {
  border: 2px dotted red !important;
}

/* ==========================
   Deprecated Attributes
   ========================== */
*[background],
*[bgcolor],
*[clear],
*[color],
*[compact],
*[noshade],
*[nowrap],
*[size],
*[start],
*[bottommargin],
*[leftmargin],
*[rightmargin],
*[topmargin],
*[marginheight],
*[marginwidth],
*[alink],
*[link],
*[text],
*[vlink],
*[align],
*[valign],
*[hspace],
*[vspace],
*[height],
*[width],
ul[type],
ol[type],
li[type] {
  border: 2px solid red !important;
}

/* ==========================
   Proposed Deprecated Elements
   ========================== */
input[type="button"],
big,
tt {
  border: 2px dotted green !important;
}

/* ==========================
   Proposed Deprecated Attributes
   ========================== */
*[border],
a[target],
table[cellpadding],
table[cellspacing],
*[name] {
  border: 2px solid green !important;
}

SassMeister-rendered.html

<div></div>

<br>

<a href="">link</a>

<br><br>

<strike>Don't use me anymore</strike>
<u>I'm deprecated</u>

<br>