如何通过 JQuery 检查选择中是否已存在选项
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How can I check whether a option already exist in select by JQuery
提问by Billy
How can I check whether a option already exist in select by JQuery?
如何通过 JQuery 检查选择中是否已存在选项？
I want to dynamically add options into select and so I need to check whether the option is already exist to prevent duplication.
我想动态地将选项添加到 select 中，因此我需要检查该选项是否已经存在以防止重复。
回答by Tamas Czinege
This evaluates to true if it already exists:
如果它已经存在，则计算结果为 true：
$("#yourSelect option[value='yourValue']").length > 0;
回答by HaMinh Nguyen
Another way using jQuery:
使用 jQuery 的另一种方式：
var exists = false;
$('#yourSelect option').each(function(){
if (this.value == yourValue) {
exists = true;
}
});
回答by Seb
if ( $("#your_select_id option[value=<enter_value_here>]").length == 0 ){
alert("option doesn't exist!");
}
回答by alnorth29
var exists = $("#yourSelect option")
.filter(function (i, o) { return o.value === yourValue; })
.length > 0;
This has the advantage of automatically escaping the value for you, which makes random quotes in the text much easier to deal with.
这具有自动为您转义值的优点，这使得文本中的随机引号更容易处理。
回答by mike
Does not work, you have to do this:
不起作用，你必须这样做：
if ( $("#your_select_id option[value='enter_value_here']").length == 0 ){
alert("option doesn't exist!");
}
回答by Sulung Nugroho
It's help me :
它帮助我：
var key = 'Hallo';
if ( $("#chosen_b option[value='"+key+"']").length == 0 ){
alert("option not exist!");
$('#chosen_b').append("<option value='"+key+"'>"+key+"</option>");
$('#chosen_b').val(key);
$('#chosen_b').trigger("chosen:updated");
}
});
回答by codeasaurus
I had a similar issue. Rather than run the search through the dom every time though the loop for the select control I saved the jquery select element in a variable and did this:
我有一个类似的问题。我没有每次都通过 dom 运行搜索，而是通过选择控件的循环将 jquery 选择元素保存在一个变量中并执行以下操作：
function isValueInSelect($select, data_value){
return $($select).children('option').map(function(index, opt){
return opt.value;
}).get().includes(data_value);
}
