javascript 如何检查我的 <select> 元素是否包含 multiple 属性
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how can I check to see if my <select> element contains the multiple attribute
提问by arrowill12
hi I have tried many options to check if the multiple attribute is set in my select box but none have worked. I am trying to determine if the current select box that I am getting values from is a multiple select so far this is what I have tried:
嗨，我尝试了很多选项来检查我的选择框中是否设置了多个属性，但没有一个有效。我正在尝试确定我从中获取值的当前选择框是否是一个多重选择，这是我尝试过的：
if($(":select[multiple]").length){
alert("worked");
}
also
还
if($("select").attr("multiple"){
alert("worked");
}
also
还
if($("select").attr("multiple") != 'undefined'{
alert("worked");
}
html:
html：
<select multiple="multiple" style="height:50px" class="classname" name="multi_values[]">
<option value="blah">blah</option>
<option value="blah">blah</option>
<option value="blah">blah</option>
</select>
回答by mgraph
remove :at the beginning of :
:在开头删除：
if($("select[multiple]").length){
alert("worked");
}
回答by Stano
Also simple javascript check:
也简单的javascript检查：
var c = document.getElementsByTagName('select'); //collection
for (var i=0, l = c.length; i<l; i++) {
alert(typeof c[i].attributes['multiple'] == 'undefined' ? 'single':'multiple');
}
And jQuery equivalent:
和 jQuery 等价的：
$('select').each(function(){
alert( typeof this.attributes['multiple'] == 'undefined' ? 'single':'multiple' );
});
回答by Chandu
All the options except ":select[multiple]"(shd be "select[multiple]") you tried should work.
除了":select[multiple]"(shd be "select[multiple]") 您尝试过的所有选项都应该有效。
JSFiddle: http://jsfiddle.net/VAXF6/2/
JSFiddle：http: //jsfiddle.net/VAXF6/2/
However you are missing a closing paran for your if statement.
但是，您缺少 if 语句的结束句。
Change your code to:
将您的代码更改为：
if($("select[multiple]").length){
alert("worked");
}
or
或者
if($("select").attr("multiple")){
alert("worked");
}
or
或者
if($("select").attr("multiple") != 'undefined'){
alert("worked");
}
Another alternative:
另一种选择：
if($("select").is("[multiple]")){
alert("worked");
}
回答by Grinn
It seems you need to only alert if multiple was set with a value, not just if it exists as an attribute:
似乎您只需要在 multiple 设置了一个值时才需要发出警报，而不仅仅是它是否作为属性存在：
if($("select[multiple='multiple']").length){
alert("worked");
}
