JQuery create new select option

问题:

I have the below functions in regular JavaScript creating select options. Is there a way I can do this with jQuery without having to use the form object? Perhaps storing the options as an array of JSON objects and parsing this in the calling function...

function populate(form)
{
form.options.length = 0;
form.options[0] = new Option("Select a city / town in Sweden","");
form.options[1] = new Option("Melbourne","Melbourne");
}

Below is how I call the function above:

populate(document.form.county); //county is the id of the dropdownlist to populate.    

回答1:

Something like:

function populate(selector) {
  $(selector)
    .append('<option value="foo">foo</option>')
    .append('<option value="bar">bar</option>')
}

populate('#myform .myselect');

Or even:

$.fn.populate = function() {
  $(this)
    .append('<option value="foo">foo</option>')
    .append('<option value="bar">bar</option>')
}

$('#myform .myselect').populate();

回答2:

What about

var option = $('<option/>');
option.attr({ 'value': 'myValue' }).text('myText');
$('#county').append(option);

回答3:

How about

$('#county').append(
    $('<option />')
        .text('Select a city / town in Sweden')
        .val(''),
    $('<option />')
        .text('Melbourne')
        .val('Melbourne')
);

回答4:

If you need to make single element you can use this construction:

$('<option/>', {
    'class': this.dataID,
    'text': this.s_dataValue
}).appendTo('.subCategory');

But if you need to print many elements you can use this construction:

function printOptions(arr){
    jQuery.each(arr, function(){
        $('<option/>', {
            'value': this.dataID,
            'text': this.s_dataValue
        }).appendTo('.subCategory');
    });
}

回答5:

This is confusing. When you say "form object", do you mean "<select> element"? If not, your code won't work, so I'll assume your form variable is in fact a reference to a <select> element. Why do you want to rewrite this code? What you have has worked in all scriptable browsers since around 1996, and won't stop working any time soon. Doing it with jQuery will immediately make your code slower, more error-prone and less compatible across browsers.

Here's a function that uses your current code as a starting point and populates a <select> element from an object:

<select id="mySelect"></select>

<script type="text/javascript>

function populateSelect(select, optionsData) {
    var options = select.options, o, selected;
    options.length = 0;
    for (var i = 0, len = optionsData.length; i < len; ++i) {
        o = optionsData[i];
        selected = !!o.selected;
        options[i] = new Option(o.text, o.value, selected, selected);
    }
}

var optionsData = [
    {
        text: "Select a city / town in Sweden",
        value: ""
    },
    {
        text: "Melbourne",
        value: "Melbourne",
        selected: true
    }
];

populateSelect(document.getElementById("mySelect"), optionsData);

</script>