To disable/prevent text selection in your pages you can use CSS user-select property. By using this property you can specifies whether the text of an element can be selected or not.
Below is the example to disable text selection using CSS
Code
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<style type="text/css">
.disable-text{
-webkit-user-select:none;
-webkit-touch-callout:none;
-moz-user-select:none;
-ms-user-select:none;
user-select:none;
}
</style>
<body>
<p>Unselectable Text</p>
<div class="disable-text">
<h1>Sample text</h1>
</div>
<div>
<p>Selectable Text</p> <h1>Sample Text</h1></div>
</body>
</html>