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<html><head><style>#ex1 { color: red;}</style></head><body><h1>The setProperty() Method</h1><p>Click the button to set a new CSS property with "important" priority.</p><button onclick="myFunction()">Try it</button><div id="ex1">Some text.</div><script>function myFunction() { var declaration = document.styleSheets[0].cssRules[0].style; var setprop = declaration.setProperty("background-color", "yellow", "important");}</script></body></html>