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<html><body><h1>JavaScript Global Methods</h1><h2>The isNaN() Method</h2><p>isNaN() returns true if a value is NaN:</p><p id="demo"></p><script>let result ="Is 123 NaN? " + isNaN(123) + "<br>" +"Is -1.23 NaN? " + isNaN(-1.23) + "<br>" +"Is 5-2 NaN? " + isNaN(5-2) + "<br>" +"Is 0 NaN? " + isNaN(0);document.getElementById("demo").innerHTML = result;</script></body></html>