1.CSS-6

<h2 id="css6"></h2>
<style>#css6::before{content:"1.CSS-6";}</style>

2.ATTR-6

<h2 data-title="2.ATTR-6" id="attr6"></h2>
<style>#attr6::before{content:attr(data-title);}</style>

3.IMG-6

<h2><img src="path/to/title6.png" alt=""></h2>

4.B64-6

// PHP GD ⇒ base64 image (see code sample)

5.SVGEM-6

<object data="title6.svg" type="image/svg+xml"></object>

6.CAN-6

<canvas id="can6" width="400" height="60"></canvas>
<script>
 const c=document.getElementById('can6').getContext('2d');
 c.font='32px Arial';c.fillText('6.CAN-6',10,40);
</script>

7.WEBGL-6

// WebGL canvas – omitted for brevity

8.JS-6

<h2 id="js6"></h2>
<script>document.getElementById('js6').innerText='8.JS-6';</script>

9.EVT-6

<h2 id="evt6">(click)</h2>
<script>document.getElementById('evt6').onclick=()=>{event.target.innerText='9.EVT-6'};</script>

10.COM-6

<h2><!--10.COM-6--></h2>
<script>...extract comment...</script>

11.ENC-6

// atob(<base64>) then inject

12.IFR-6

<iframe src="title6.html"></iframe>

13.PDF-6

<embed src="title6.pdf" type="application/pdf">

14.FNT-6

// custom icon font glyphs

15.FRM-6

<input value="15.FRM-6" disabled>

16.OBJ-6

<object data="title6-content.html"></object>

17.EMB-6

<embed src="title6-content.html">

18.SHD-6

<h2 is="shadow-title-6"></h2>
<script>
 class ShadowTitle6 extends HTMLHeadingElement{
   constructor(){super();const s=this.attachShadow({mode:'closed'});
   const span=document.createElement('span');span.textContent='18.SHD-6';s.appendChild(span);}
 }
 customElements.define('shadow-title-6',ShadowTitle6,{extends:'h2'});
</script>

19.B64SVG-6

// <img src="data:image/svg+xml;base64,...">

20.XHR-6

<h2 id="xhr6"></h2>
<script>fetch('title6.txt').then(r=>r.text()).then(t=>xhr6.innerText=t);</script>