答案 0 :(得分:4)
.val()
doesn't work for disabled elements,请使用selectedIndex()
$(document).ready(function() {
$("#submit").click(function() {
if ($("#brand_bu").prop('selectedIndex') != "0") {
$("#hide").hide();
$("#show").show();
}
});
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select id="brand_bu" name="selected" class="form-control" onchange="panelHeader()">
<option value="1" disabled selected>Please Select a Option..</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
</select>
<span class="input-group-btn">
<button class="btn btn-primary" id="submit" type="button">Refresh Table</button>
</span>
<div id='hide'>hide</div>
<div id='show'>show</div>
&#13;
答案 1 :(得分:0)
{ \"newsletter\":\r\n {\r\n \"properties\": {\r\n \"key1\" : \"value1\",\r\n \"key2\" : \"value2\",\r\n \"key3\" : \"value3\"\r\n }\r\n }\r\n }
我更改了你的html代码和js代码。请查看jsfiddle。