How to display the snack bar on page load : <p>Hi i want to show snack bar on my page after the page load without any clicking. I have a piece of code but it works in onclick. But i want to show the message without any click after the page load. </p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>function snackBar() {
    var x = document.getElementById("snackbar")
    x.className = "show";
    setTimeout(function(){ x.className = x.className.replace("show", ""); }, 3000);
}</code></pre>
<pre class="snippet-code-css lang-css prettyprint-override"><code>#snackbar {
    visibility: hidden;
    min-width: 250px;
    margin-left: -125px;
    background-color: #333;
    color: #fff;
    text-align: center;
    border-radius: 2px;
    padding: 16px;
    position: fixed;
    z-index: 1;
    right:0;
    bottom: 30px;
    font-size: 17px;
}

#snackbar.show {
    visibility: visible;
    -webkit-animation: fadein 0.5s, fadeout 0.5s 2.5s;
    animation: fadein 0.5s, fadeout 0.5s 2.5s;
}

@-webkit-keyframes fadein {
    from {bottom: 0; opacity: 0;} 
    to {bottom: 30px; opacity: 1;}
}

@keyframes fadein {
    from {bottom: 0; opacity: 0;}
    to {bottom: 30px; opacity: 1;}
}

@-webkit-keyframes fadeout {
    from {bottom: 30px; opacity: 1;} 
    to {bottom: 0; opacity: 0;}
}

@keyframes fadeout {
    from {bottom: 30px; opacity: 1;}
    to {bottom: 0; opacity: 0;}
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;button onclick="snackBar()"&gt;Show Snackbar&lt;/button&gt;

&lt;div id="snackbar"&gt;Some text some message..&lt;/div&gt;</code></pre>
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