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<html><body><input type="week" id="myWeek" value="2014-W15"><p>Click the button to increment the value of the week field by 10 weeks (each time you click).</p><button onclick="myFunction()">Try it</button><p><strong>Note:</strong> input elements with type="week" are not supported in Firefox.</p><script>function myFunction() { document.getElementById("myWeek").stepUp(10);}</script></body></html>