Javascript/jQuery: Set Values (Selection) in a mul

问题:

I have a multiple select:

<select name='strings' id="strings" multiple style="width:100px;">
    <option value="Test">Test</option>
    <option value="Prof">Prof</option>
    <option value="Live">Live</option>
    <option value="Off">Off</option>
    <option value="On">On</option>
</select>

I load data from my database. Then I have a string like this:

var values="Test,Prof,Off";

How can I set this Values in the multiple select? Already tried change the string in an array and put it as value in the multiple, but doesnt work...! Can someone help me with this? THANKS!!!

回答1:

Iterate through the loop using the value in a dynamic selector that utilizes the attribute selector.

var values="Test,Prof,Off";
$.each(values.split(","), function(i,e){
    $("#strings option[value='" + e + "']").prop("selected", true);
});

Working Example http://jsfiddle.net/McddQ/1/

回答2:

in jQuery:

$("#strings").val(["Test", "Prof", "Off"]);

or in pure JavaScript:

var element = document.getElementById('strings');
var values = ["Test", "Prof", "Off"];
for (var i = 0; i < element.options.length; i++) {
    element.options[i].selected = values.indexOf(element.options[i].value) >= 0;
}

jQuery does significant abstraction here.

回答3:

Just provide the jQuery val function with an array of values:

var values = "Test,Prof,Off";
$('#strings').val(values.split(','));

And to get the selected values in the same format:

values = $('#strings').val();

回答4:

Pure JavaScript ES6 solution

• Catch every option with a querySelectorAll function and split the values string.
• Use Array#forEach to iterate over every element from the values array.
• Use Array#find to find the option matching given value.
• Set it's selected attribute to true.

Note: Array#from transforms an array-like object into an array and then you are able to use Array.prototype functions on it, like find or map.

var values = "Test,Prof,Off",
    options = Array.from(document.querySelectorAll('#strings option'));

values.split(',').forEach(function(v) {
  options.find(c => c.value == v).selected = true;
});

<select name='strings' id="strings" multiple style="width:100px;">
    <option value="Test">Test</option>
    <option value="Prof">Prof</option>
    <option value="Live">Live</option>
    <option value="Off">Off</option>
    <option value="On">On</option>
</select>

回答5:

Basically do a values.split(',') and then loop through the resulting array and set the Select.

回答6:

Pure JavaScript ES5 solution

For some reason you don't use jQuery nor ES6? This might help you:

var values = "Test,Prof,Off";
var splitValues = values.split(',');
var multi = document.getElementById('strings');

multi.value = null; // Reset pre-selected options (just in case)
var multiLen = multi.options.length;
for (var i = 0; i < multiLen; i++) {
  if (splitValues.indexOf(multi.options[i].value) >= 0) {
    multi.options[i].selected = true;
  }
}

<select name='strings' id="strings" multiple style="width:100px;">
    <option value="Test">Test</option>
    <option value="Prof">Prof</option>
    <option value="Live">Live</option>
    <option value="Off">Off</option>
    <option value="On" selected>On</option>
</select>

回答7:

var groups = ["Test", "Prof","Off"];

    $('#fruits option').filter(function() {
      return groups.indexOf($(this).text()) > -1; //Options text exists in array
    }).prop('selected', true); //Set selected