some

mfracZcomp-20

Fairly comprehensive test of many mfrac properties

W3C sample WIRIS
Inline double down arrows, display style, thick line  ⇓ sin ⁡ θ M ⇓  the end. 
<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mtext>Inline double down arrows, display style, thick line </mtext>
  <mstyle displaystyle="false" scriptlevel="0">
    <mrow>
      <mo form="prefix" fence="true" stretchy="true" lspace="0em" rspace="0em">&#x021D3;</mo>
      <mrow>
        <mstyle displaystyle="true" scriptlevel="0">
          <mfrac linethickness="1pt">
            <mrow>
              <mi mathcolor="gray">sin</mi>
              <mo rspace="verythinmathspace">&#x02061;</mo>
              <mi>&#x003B8;</mi>
            </mrow>
            <mi>M</mi>
          </mfrac>
        </mstyle>
      </mrow>
      <mo form="postfix" fence="true" stretchy="true" lspace="0em" rspace="0em">&#x021D3;</mo>
    </mrow>
  </mstyle>
  <mtext> the end.</mtext>
</math>

Author: Mackichan