File Change Preview

Shows the changes an AI wants to make to a file, with removed lines in red and added lines in green, and buttons to accept or reject.

Download the file Open full screen

One HTML file with the CSS and JavaScript inside. No library needed. MIT license.

Live preview

How to use it

Click Copy the code, or download the file.
Paste the CSS into your stylesheet, the HTML where you want the component, and the script before the closing body tag.
Change --accent at the top of the CSS to your brand color, then connect the events to your AI service.

What you get

Works in light and dark mode automatically
Keyboard friendly, with labels for screen readers
Fits phones, tablets and desktops
Respects the reduced motion setting
No framework, so it works with any stack

The code

<!DOCTYPE html>
<!--
  File Change Preview: a free AI UI component
  From 100 Free AI UI Components by MM Rahman Bappi, MIT license
  https://mmrahmanbappi.github.io/100-free-ai-ui-components/

  How to use: copy the CSS, HTML and JavaScript below into your page.
  Colors are CSS variables at the top. Change --accent to match your brand.
  Light and dark themes follow the visitor's system setting, or set
  data-theme="dark" or data-theme="light" on the html element.
-->
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>File Change Preview | Free AI UI Component</title>
<meta name="description" content="Shows the changes an AI wants to make to a file, with removed lines in red and added lines in green, and buttons to accept or reject.">
<meta name="robots" content="noindex, follow">
<style>
:root{
  --accent:#5b5bd6; --accent-ink:#fff; --accent-soft:#ececfc;
  --bg:#f7f7f8; --surface:#fff; --surface-2:#f1f1f4; --ink:#17171c; --text:#3a3a44; --muted:#6c6c78;
  --line:#e3e3e8; --good:#15803d; --warn:#b45309; --bad:#c62828;
  --radius:14px; --shadow:0 1px 2px rgba(20,20,30,.06),0 8px 24px -12px rgba(20,20,30,.18);
  --font:system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,sans-serif; --mono:ui-monospace,"Cascadia Code",Menlo,Consolas,monospace;
}
@media (prefers-color-scheme:dark){:root:not([data-theme=light]){
  --accent:#8b8bff; --accent-ink:#0f0f16; --accent-soft:#25254a;
  --bg:#0f0f13; --surface:#18181f; --surface-2:#212129; --ink:#f3f3f6; --text:#d4d4dc; --muted:#9a9aa8;
  --line:#2c2c36; --good:#4ade80; --warn:#fbbf24; --bad:#f87171; --shadow:0 1px 2px rgba(0,0,0,.4),0 10px 30px -12px rgba(0,0,0,.6);
}}
:root[data-theme=dark]{
  --accent:#8b8bff; --accent-ink:#0f0f16; --accent-soft:#25254a;
  --bg:#0f0f13; --surface:#18181f; --surface-2:#212129; --ink:#f3f3f6; --text:#d4d4dc; --muted:#9a9aa8;
  --line:#2c2c36; --good:#4ade80; --warn:#fbbf24; --bad:#f87171; --shadow:0 1px 2px rgba(0,0,0,.4),0 10px 30px -12px rgba(0,0,0,.6);
}
*{box-sizing:border-box}
html,body{margin:0}
body{min-height:100vh;display:grid;grid-template-columns:minmax(0,1fr);place-items:center;padding:24px;background:var(--bg);color:var(--text);font:15px/1.5 var(--font);-webkit-font-smoothing:antialiased}
button,input,textarea,select{font:inherit;color:inherit}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
[hidden]{display:none!important}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
@media (prefers-reduced-motion:reduce){*,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition:none!important}}
/* ---- component ---- */
.wrap{width:min(100%,620px);display:flex;flex-direction:column;gap:14px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:16px 18px}
.card h2{font-size:15px;margin:0 0 4px;color:var(--ink)}
.muted{color:var(--muted);font-size:13px}
.num{font-variant-numeric:tabular-nums}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;border:1px solid var(--line);background:var(--surface);color:var(--ink);border-radius:10px;padding:8px 14px;font-size:14px;font-weight:600;cursor:pointer}
.btn:hover{border-color:var(--accent)}.btn.pri{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}.btn:disabled{opacity:.45;cursor:not-allowed}
.btn.sm{padding:5px 10px;font-size:13px;border-radius:8px}
.ib{width:28px;height:28px;display:grid;place-items:center;border:0;background:none;color:var(--muted);border-radius:7px;cursor:pointer;flex:none}
.ib:hover{background:var(--surface-2);color:var(--ink)}.ib:disabled{opacity:.3;cursor:not-allowed}
.pill{display:inline-flex;align-items:center;gap:5px;font-size:12px;font-weight:600;border-radius:99px;padding:2px 9px;border:1px solid}
.pill.run{color:var(--accent);border-color:color-mix(in srgb,var(--accent) 40%,var(--line))}
.pill.ok{color:var(--good);border-color:color-mix(in srgb,var(--good) 40%,var(--line))}
.pill.bad{color:var(--bad);border-color:color-mix(in srgb,var(--bad) 40%,var(--line))}
.pill.wait{color:var(--muted);border-color:var(--line)}
pre{margin:0;font:12.5px/1.55 var(--mono);background:var(--surface-2);border:1px solid var(--line);border-radius:10px;padding:10px 12px;overflow-x:auto;color:var(--ink)}
.tg{width:40px;height:23px;border-radius:99px;background:var(--line);position:relative;flex:none;border:0;cursor:pointer;padding:0}
.tg::after{content:"";position:absolute;top:3px;left:3px;width:17px;height:17px;border-radius:50%;background:#fff;transition:left .15s}
.tg[aria-checked=true]{background:var(--accent)}.tg[aria-checked=true]::after{left:20px}
.wrap{width:min(100%,680px)}
.diff{border:1px solid var(--line);border-radius:12px;overflow:hidden;background:var(--surface)}
.dh{display:flex;align-items:center;gap:10px;padding:9px 12px;border-bottom:1px solid var(--line);background:var(--surface-2);font:13px var(--mono);color:var(--ink);flex-wrap:wrap}
.dh .add{color:color-mix(in srgb,var(--good) 85%,var(--ink))}.dh .del{color:var(--bad)}.dh .sp{flex:1}
.lines{overflow-x:auto;font:12.5px/1.6 var(--mono)}
.ln{display:grid;grid-template-columns:36px 36px 18px 1fr;white-space:pre;min-width:max-content}
.ln span{padding:0 8px;color:var(--muted);text-align:right;user-select:none}
.ln code{padding-right:14px;color:var(--ink)}
.ln.a{background:color-mix(in srgb,var(--good) 12%,transparent)}.ln.a .s{color:var(--good)}
.ln.d{background:color-mix(in srgb,var(--bad) 12%,transparent)}.ln.d .s{color:var(--bad)}
.acts{display:flex;justify-content:flex-end;gap:8px;padding:10px 12px;border-top:1px solid var(--line)}
.res{padding:12px;font-size:14px;font-weight:600;text-align:center}
</style>
</head>
<body>
<div class="wrap"><div class="diff" id="d">
  <div class="dh"><span>src/utils/price.js</span><span class="add">+3</span><span class="del">-2</span><span class="sp"></span></div>
  <div class="lines" id="lines" role="table" aria-label="Changes to price.js"></div>
  <div class="acts" id="acts"><button class="btn sm" type="button" id="rj">Reject</button><button class="btn sm pri" type="button" id="ac">Accept changes</button></div>
</div></div>
<script>
// Demo helper: add ?theme=dark or ?theme=light to the address to preview a theme.
(function(){var t=new URLSearchParams(location.search).get('theme');if(t)document.documentElement.dataset.theme=t;})();
var L=[[' ',1,1,'export function formatPrice(amount) {'],['-',2,null,'  return "$" + amount;'],['+',null,2,'  const value = Number(amount) || 0;'],['+',null,3,'  return value.toLocaleString("en-US", {'],['+',null,4,'    style: "currency", currency: "USD" });'],
[' ',3,5,'}'],[' ',4,6,''],['-',5,null,'// TODO: handle cents'],[' ',6,7,'export const TAX_RATE = 0.2;']];
var lines=document.getElementById('lines'),acts=document.getElementById('acts');
L.forEach(function(l){var d=document.createElement('div');d.className='ln'+(l[0]==='+'?' a':l[0]==='-'?' d':'');d.setAttribute('role','row');
  d.innerHTML='<span role="cell"></span><span role="cell"></span><span class="s" role="cell" aria-label="'+(l[0]==='+'?'added':l[0]==='-'?'removed':'unchanged')+'"></span><code role="cell"></code>';
  var c=d.children;c[0].textContent=l[1]||'';c[1].textContent=l[2]||'';c[2].textContent=l[0].trim();c[3].textContent=l[3];lines.appendChild(d);});
function done(msg,cls){acts.outerHTML='<div class="res" role="status" style="color:var(--'+cls+')">'+msg+'</div>';}
document.getElementById('ac').addEventListener('click',function(){done('Changes applied to price.js','good');});
document.getElementById('rj').addEventListener('click',function(){done('Changes rejected. The file was not changed.','muted');});
</script>
</body>
</html>

More agents and tools components

Tool Call Card
Shows that the AI used a tool, with its name, status and time. Open it to see the exact input and the result it got back.
Action Approval Request
Before an agent does something important, like sending an email, it shows exactly what it will do and waits for Allow or Deny.
Editable Task Plan
The agent proposes a step by step plan before it starts. People can reorder, edit or remove steps, then approve the plan to run it.
Agent Activity Timeline
A timeline of everything an agent did: its thinking, tool calls, results and messages, with times and a filter by type.
Web Results Card
A card listing the web pages an AI read, with title, site and a short excerpt. Pages it used in the answer are marked.
Agent Run Log
A terminal style log that streams what an agent is doing, with colored levels, a pause button, auto scroll and copy.

File Change Preview

How to use it

What you get

The code

More agents and tools components

Tool Call Card

Action Approval Request

Editable Task Plan

Agent Activity Timeline

Web Results Card

Agent Run Log