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<html><body><h1>The Console Object</h1><h2>The assert() Method</h2><p>Remember to open the console (Press F12) before you click "Run".</p><script>console.assert(document.getElementById("demo"), "You have no element with ID 'demo'");</script></body><!-- Mirrored from www.w3schools.com/jsref/tryit.asp?filename=tryjsref_console_assert4 by HTTrack Website Copier/3.x [XR&CO'2014], Wed, 21 Dec 2022 17:39:29 GMT --></html>