How to use code for MATH MML in Jquery in XML Parser

Question

Using JQuery XML Parser everything works well. I have Codes for Equation , while i try to find the code its return none. But code is actually in XML. I dont know the exact reason why it doesnt find. May be the xml node contain ":" that is the reason or not. Can you help me to find the code mml:math

XML Code

<p>
  <disp-formula id="disp-formula3-xxxx">
    <label>(3)</label>
    <alternatives>
      <mml:math id="math15-xxxx" display="block">
        <mml:mrow>
          <mml:mi mathvariant="normal">Risk</mml:mi>
          <mml:mo>=</mml:mo>
          <mml:mstyle displaystyle="true">
            <mml:mrow>
              <mml:mo>&#x0222B;</mml:mo>
            </mml:mrow>
          </mml:mstyle>
          <mml:mi mathvariant="double-struck">P</mml:mi>
          <mml:mspace width="0.25em"/>
          <mml:mspace width="0.25em"/>
          <mml:mo stretchy="false">[</mml:mo>
          <mml:mi mathvariant="normal">Load Events</mml:mi>
          <mml:mo stretchy="false">]</mml:mo>
          <mml:mo>&#x000D7;</mml:mo>
          <mml:mi mathvariant="double-struck">P</mml:mi>
          <mml:mspace width="0.25em"/>
          <mml:mo stretchy="false">[</mml:mo>
          <mml:mi mathvariant="normal">Responses</mml:mi>
          <mml:mo>|</mml:mo>
          <mml:mi mathvariant="normal">Loads</mml:mi>
          <mml:mo stretchy="false">]</mml:mo>
          <mml:mo>&#x000D7;</mml:mo>
          <mml:mi mathvariant="double-struck">C</mml:mi>
          <mml:mspace width="0.25em"/>
          <mml:mo stretchy="false">[</mml:mo>
          <mml:mi mathvariant="normal">Loads</mml:mi>
          <mml:mo>,</mml:mo>
          <mml:mi mathvariant="normal">Responses</mml:mi>
          <mml:mo stretchy="false">]</mml:mo>
        </mml:mrow>
      </mml:math>
      <graphic xlink:href="10.1177_1687814018802531-eq3.tif"/>
    </alternatives>
  </disp-formula>
</p>

In JQUERY

alert($xml.find("mml:math").length)

it returns zero. i have to check lot of coding based on Math MML code. Can you help me to understand whats the problem here

Answer 1

To use any of the meta-characters ( such as !"#$%&'()*+,./:;<=>?@[\]^`{|}~ ) as a literal part of a name, it must be escaped with with two backslashes: \\. docs

So you need to escape : in your selector and use

$xml.find("mml\\:math").length

var $xml = $.parseXML($("#xml").html().trim());
var leng = $($xml).find('mml\\:math').length;
console.log(leng);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="xml">
  <p>
    <disp-formula id="disp-formula3-xxxx">
      <label>(3)</label>
      <alternatives>
        <mml:math id="math15-xxxx" display="block">
          <mml:mrow>
            <mml:mi mathvariant="normal">Risk</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mstyle displaystyle="true">
              <mml:mrow>
                <mml:mo>&#x0222B;</mml:mo>
              </mml:mrow>
            </mml:mstyle>
            <mml:mi mathvariant="double-struck">P</mml:mi>
            <mml:mspace width="0.25em"/>
            <mml:mspace width="0.25em"/>
            <mml:mo stretchy="false">[</mml:mo>
            <mml:mi mathvariant="normal">Load Events</mml:mi>
            <mml:mo stretchy="false">]</mml:mo>
            <mml:mo>&#x000D7;</mml:mo>
            <mml:mi mathvariant="double-struck">P</mml:mi>
            <mml:mspace width="0.25em"/>
            <mml:mo stretchy="false">[</mml:mo>
            <mml:mi mathvariant="normal">Responses</mml:mi>
            <mml:mo>|</mml:mo>
            <mml:mi mathvariant="normal">Loads</mml:mi>
            <mml:mo stretchy="false">]</mml:mo>
            <mml:mo>&#x000D7;</mml:mo>
            <mml:mi mathvariant="double-struck">C</mml:mi>
            <mml:mspace width="0.25em"/>
            <mml:mo stretchy="false">[</mml:mo>
            <mml:mi mathvariant="normal">Loads</mml:mi>
            <mml:mo>,</mml:mo>
            <mml:mi mathvariant="normal">Responses</mml:mi>
            <mml:mo stretchy="false">]</mml:mo>
          </mml:mrow>
        </mml:math>
        <graphic xlink:href="10.1177_1687814018802531-eq3.tif"/>
      </alternatives>
    </disp-formula>
  </p>
</div>