blocks|key|5379414|text|要使用javascript确定SELECT中的选项数量，请执行以下操作：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5379415|if+(document.getElementById('SCname').options.length+==+1+){++//+1+because+it+looks+like+you+automatically+added+1+via+HTML
}|code-block|syntax|javascript|5379416|或jQuery：|5379417|if+($('#SCname+option').length+==+1)+{...}|5379418|如果您询问如何确定当前选择的选项或选项的数量，则不是完全清楚。|5379419|entityMap^0|F|6|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|Y|8|@]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|R|$]]

To determine the number of options in the <code>SELECT</code>, using javascript:

<pre><code>if (document.getElementById('SCname').options.length == 1 ){ // 1 because it looks like you automatically added 1 via HTML
}
</code></pre>

or jQuery:

<pre><code>if ($('#SCname option').length == 1) {...}
</code></pre>

It's not entirely clear if you asking how to determine the current selected option or the number of options...

blocks|key|5325196|text|由于您使用的是jQuery，因此请使用++方法|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|5325197|if+($("#SCname").val()+!==+"")+{+
++//+...+The+selection+is+not+empty.
}|code-block|syntax|javascript|5325198|注意:这要求你的"+empty“选项有一个空值：value=""__。|CODE|5325199|5325200|5325201|如果您还想检查option+elements是否存在，请在select菜单中执行以下操作：|5325202|var+mySelect+=+$("#SCname");
if+(mySelect.val()!==""+&&+mySelect.find("option").length>0)+{+
++//+...+The+selection+is+_not_+empty.
}|5325203|entityMap^0|L|2|0|0|O|8|0|0|0|7|6|E|V|7|6|T|6|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Z|8|@$9|10|A|11|B|M]]|D|@]|E|$]]|$1|N|3|-4|5|6|7|12|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|13|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|14|8|@$9|15|A|16|B|C]|$9|17|A|18|B|C]|$9|19|A|1A|B|M]|$9|1B|A|1C|B|M]]|D|@]|E|$]]|$1|R|3|S|5|H|7|1D|8|@]|D|@]|E|$I|J]]|$1|T|3|-4|5|6|7|1E|8|@]|D|@]|E|$]]]|U|$]]

Since you are using jQuery, use the <a href="http://api.jquery.com/val/" rel="nofollow"><code>.val()</code></a> method:

<pre><code>if ($("#SCname").val() !== "") { 
 // ... The selection is not empty.
}
</code></pre>

Note: this requires that you're "empty" option has an empty value: <code>value=""</code>.

<a href="http://jsfiddle.net/cfalk/b84kn/8/" rel="nofollow">Example</a>

<hr>

If you also want to check if <code>option</code> elements exist in the <code>select</code> menu:

<pre><code>var mySelect = $("#SCname");
if (mySelect.val()!=="" &amp;&amp; mySelect.find("option").length&gt;0) { 
 // ... The selection is _not_ empty.
}
</code></pre>

blocks|key|1120550|text|您可以在select+element选项上使用JQuery+size()方法，该方法将返回元素的数量(该数字应大于1，因为您持有的是默认元素)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|BOLD|entityRanges|data|1120551|if+($('#SCname+option').size()+>+1)
{
++//+Do+some+stuff
}|code-block|syntax|javascript|1120552|1120553|也许我误解了你的逻辑，但是，我要告诉你，既然你是动态添加option元素，为什么不在做任何额外的处理之前检查employees对象的长度：|1120554|var+html+=+'';
if+(json.employees.length+>+0)+//+Check+your+array+size
{
++for+(var+i+=+0;+i+<+json.employees.length;+i%2B%2B)+
++{+
++++var+firstName+=+json.employees[i].firstName;
++++var+lastName+=+json.employees[i].lastName;+html+%2B=+''%2BlastName%2B'';+
++}+
++$('#SCname').append(html);+
++$('#SCname').show();
}|1120555|entityMap^0|U|6|1L|1|0|0|0|1I|9|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|D]]|E|@]|F|$]]|$1|G|3|H|5|I|7|X|8|@]|E|@]|F|$J|K]]|$1|L|3|-4|5|6|7|Y|8|@]|E|@]|F|$]]|$1|M|3|N|5|6|7|Z|8|@$9|10|A|11|B|C]]|E|@]|F|$]]|$1|O|3|P|5|I|7|12|8|@]|E|@]|F|$J|K]]|$1|Q|3|-4|5|6|7|13|8|@]|E|@]|F|$]]]|R|$]]

You can use the JQuery <code>size()</code> method on the select element option which will return the number of elements (This number should be greater than 1 since you are holding a default element):

<pre class="lang-js prettyprint-override"><code>if ($('#SCname option').size() &gt; 1)
{
 // Do some stuff
}
</code></pre>

<hr>

Maybe I misuderstood your logic but, I would tell that since you are dynamically appending option elements, why not just check the lenght of <code>employees</code> object before doing any additional processing:

<pre class="lang-js prettyprint-override"><code>var html = '';
if (json.employees.length &gt; 0) // Check your array size
{
 for (var i = 0; i &lt; json.employees.length; i++) 
 { 
 var firstName = json.employees[i].firstName;
 var lastName = json.employees[i].lastName; html += ''+lastName+''; 
 } 
 $('#SCname').append(html); 
 $('#SCname').show();
}
</code></pre>

In Order to stop multiple requests to server incase if the HTML Selection option is not empty 

Could anybody please let me know how to check if the HTML Select is not empty 

This is my HTML 

<pre class="lang-html prettyprint-override"><code>&lt;select name="" id="SCname"&gt;
 &lt;option selected="true" style="display:none;"&gt;Select Screen&lt;/option&gt;
&lt;/select&gt;
</code></pre>

<pre class="lang-js prettyprint-override"><code>var json = {
 "employees": [
 {
 "firstName": "John",
 "lastName": "Doe"
 },
 {
 "firstName": "Anna",
 "lastName": "Smith"
 },
 {
 "firstName": "Peter",
 "lastName": "Jones"
 }
 ]
};
var html = '';
for (var i = 0; i &lt; json.employees.length; i++) {
 var firstName = json.employees[i].firstName; 
 var lastName = json.employees[i].lastName;
 html += '&lt;option value="'+firstName+'"&gt;'+lastName+'&lt;/option&gt;';
}
$('#SCname').append(html);
$('#SCname').show();
</code></pre>

Could anybody please tell me how to check if this is empty or not ??

This is my <a href="http://jsfiddle.net/b84kn/" rel="nofollow">jsfiddle</a>.

How to check if the HTML selection option contains any values in it

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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为了在HTML选择选项不为空的情况下停止对服务器的多个请求谁能告诉我如何检查HTML Select是否为空这是我的HTML<select name="" id="SCname"> <option selected="true" style="display:none;">Select Screen</optio...

问如何检查HTML选择选项中是否包含任何值
EN

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问如何检查HTML选择选项中是否包含任何值EN