Jquery Select Box Validation.You can Alert Message via alert or Put message in Div as per your requirements.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<div id="message"></div>_x000D_
<form method="post">_x000D_
<select name="year" id="year">_x000D_
<option value="0">Year</option>_x000D_
<option value="1">1919</option>_x000D_
<option value="2">1920</option>_x000D_
<option value="3">1921</option>_x000D_
<option value="4">1922</option>_x000D_
</select>_x000D_
<button id="clickme">Click</button>_x000D_
</form>_x000D_
<script>_x000D_
$("#clickme").click(function(){_x000D_
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if( $("#year option:selected").val()=='0'){_x000D_
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alert("Please select one option at least");_x000D_
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$("#message").html("Select At least one option");_x000D_
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}_x000D_
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});_x000D_
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</script>
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