<head>
    <style>
        .box {
          width: 200px;
          height: 200px;
          background-color: silver;
          filter: url(#filter);
        }
        
        svg {
            display: none; 
        }
    </style>
</head>
<body>
   <svg xmlns="http://www.w3.org/2000/svg" width="0" height="0" version="1.1">
    <defs>
        <filter id="filter">
            <feTurbulence type="turbulence" baseFrequency="0.01" numOctaves="1" seed="5" stitchTiles="stitch"/>
            <feColorMatrix type="saturate" values="0"/>
            <feComponentTransfer>
                <feFuncR type="linear" slope="0" intercept="0"/>
                <feFuncG type="linear" slope="0" intercept="0.5"/>
                <feFuncB type="linear" slope="0" intercept="0"/>
                <feFuncA type="linear" slope="0" intercept="1"/>
            </feComponentTransfer>
        </filter>
    </defs>
  </svg>
  <div class="box"></div>
</body>