Inline CSS or Javascript in Admin Backend CMS or Static Bloc

CMS Page Backend :

CMS → Pages → Page Information → Design

<script type="text/javascript">your code</script>

sample

<script type="text/javascript" src="//ssp.adskom.com/tags/third-party-async/NjkzNWI2MDYtNzAxNy00NTM3LTljNTQtOTMyZDFmM2RkYjE4" async="true"></script>

Backend Static Block :

CMS → Static Blocks → Content

<script type="text/javascript">// <![CDATA[
   you javascript code
// ]]></script>

sample

<script type="text/javascript">// <![CDATA[
function myFunction() {
  var element = document.getElementById("flag-contain");
  element.classList.toggle("flagstyle");

  var element = document.getElementById("arrow-country");
  element.classList.toggle("arrowcountry");
}
// ]]></script>

Custom Layout Update on Category (via backend) :

Catalog → Manage Categories → Category → Custom Design → Custom Layout Update

'<reference name="head">
    <block type="core/text" name="some_name" as="some_name">
        <action method="setText">
            <text><![CDATA[<script>your code</script>]]></text>
        </action>
    </block>
    <block type="core/text" name="your.block.name">
        <action method="setText">
            <text><![CDATA[<script type="text/javascript">your code</script>]]></text>
        </action>
    </block>
</reference>'

sample

'<reference name="head">
    <block type="core/text" name="some_name" as="some_name">
        <action method="setText">
            <text><![CDATA[<script async="true" src="//ssp.adskom.com/tags/third-party-async/NzFmZDdkZmMtZDZlMC00MTFlLWJmZTAtNzY2NmZkMjE4ZGM3"></script>]]></text>
        </action>
    </block>
    <block type="core/text" name="your.block.name">
        <action method="setText">
            <text><![CDATA[<script type="text/javascript">window.location = "https://www.sophieparis.com/special-promo/promo.html";</script>]]></text>
        </action>
    </block>
</reference>'

XML Update Layout in CMS Page (via backend) :

CMS → Pages → Page Information → Design → Layout Update XML

'<reference name="head">
   <block type="core/text" name="custom_css">
      <action method="setText">
          <text><![CDATA[
             <style  type="text/css">
                cms code in here
             </style> ]]>
        </text>
    </action>
   </block>
</reference>'

sample :

'<reference name="head">
   <block type="core/text" name="custom_css">
      <action method="setText">
          <text><![CDATA[
             <style  type="text/css">
                @media only screen  and (max-width : 767px) {
                   .homepage-our-brand-product {
                       padding-top: 25px !important;
                       -webkit-padding-before: 25px !important;
                   }
                }
                .homepage-banner-top .banner-right {
                   padding-top: 0px;
                   position: relative;
                   top: -100px;
                }
             </style> ]]>
        </text>
    </action>
   </block>
</reference>'