How to use placeholder as default value in select2 framework

问题

To get the chosen value of a select2 I'm using:

var x = $("#select").select2('data');
var select_choice = x.text

The problem is this throws an error if not value has been selected and I was wondering if there was any way to make it return the placeholder if no option is selected

回答1:

You have to add an empty option (i.e. <option></option>) as a first element to see a placeholder.

From Select2 official documentation :

"Note that because browsers assume the first option element is selected in non-multi-value select boxes an empty first option element must be provided (<option></option>) for the placeholder to work."

Hope this helps.

Example:

<select id="countries">
    <option></option>
    <option value="1">Germany</option>
    <option value="2">France</option>
    <option value="3">Spain</option>
</select>

and the Javascript would be:

$('#countries').select2({
    placeholder: "Please select a country"
});

回答2:

Put this in your script file:

$('select').select2({
    minimumResultsForSearch: -1,
    placeholder: function(){
        $(this).data('placeholder');
    }
});

And then in HTML, add the following code:

<select data-placeholder="Your Placeholder" multiple>
    <option></option> <------ this is where your placeholder data will appear
    <option>Value 1</option>
    <option>Value 2</option>
    <option>Value 3</option>
    <option>Value 4</option>
    <option>Value 5</option>
</select>

回答3:

$("#e2").select2({
   placeholder: "Select a State",
   allowClear: true
});
$("#e2_2").select2({
   placeholder: "Select a State"
});

The placeholder can be declared via a data-placeholder attribute attached to the select, or via the placeholder configuration element as seen in the example code.

When placeholder is used for a non-multi-value select box, it requires that you include an empty tag as your first option.

Optionally, a clear button (visible once a selection is made) is available to reset the select box back to the placeholder value.

https://select2.org/placeholders

回答4:

$('#ddlSelect').prepend('<option selected=""></option>').select2({placeholder: "Select Month"});

回答5:

This worked for me:

$('#SelectListId').prepend('<option selected></option>').select2({
    placeholder: "Select Month",
    allowClear: true
});

Hope this help :)

回答6:

Use a empty placeholder on your html like:

<select class="select2" placeholder = "">
    <option value="1">red</option>
    <option value="2">blue</option>
</select>

and in your script use:

$(".select2").select2({
        placeholder: "Select a color",
        allowClear: true
    });

回答7:

I did the following:

var defaultOption = new Option();
defaultOption.selected = true;    
$(".js-select2").append(defaultOption);

For other options I use then:

var realOption = new Option("Option Value", "id");
realOption.selected = false;    
$(".js-select2").append(realOption);

回答8:

you can init placeholder in you select html code in two level such as:

<select class="form-control select2" style="width: 100%;" data-placeholder="Select a State">
   <option></option>
   <option>تهران</option>
   <option>مشهد</option>
   <option>اصفهان</option>
   <option>شیراز</option>
   <option>اهواز</option>
   <option>تبریز</option>
   <option>کرج</option>   
</select>

1.set data-placeholder attribute in your select tag 2.set empty tag in first of your select tag

回答9:

Try this.In html you write the following code.

<select class="select2" multiple="multiple" placeholder="Select State">
    <option value="AK">Alaska</option>
    <option value="HI">Hawaii</option>
</select>

And in your script write the below code.Keep in mind that have the link of select2js.

<script>
         $( ".select2" ).select2( { } );
 </script>

回答10:

The simplest way to add empty "option" before all.

<option></option>

Example:

<select class="select2" lang="ru" tabindex="-1">
    <option></option>
    <option value="AK">Alaska</option>
    <option value="HI">Hawaii</option>
</select>

Also js code, if you need:

$(document).ready(function() {
    $(".select2").select2({
            placeholder: "Select a state",
            allowClear: true
        });
    });
}

回答11:

$selectElement.select2({
    minimumResultsForSearch: -1,
    placeholder: 'SelectRelatives'}).on('select2-opening', function() {                                                                       $(this).closest('li').find('input').attr('placeholder','Select Relative');                            
});

来源：https://stackoverflow.com/questions/21413241/how-to-use-placeholder-as-default-value-in-select2-framework