jQuery，用于选择没有价值的选项或特定文本

Question

I have selects which all have a top option with text "All" and no value, but I need to write some code that works on all other options in these selects.

I have code as follow that works, but I'd rather do away with the conditional on the second line. I did try using jQuery's ':not' selector but couldn't figure out how to configure it for missing/null/undefined value. Would it best if I explicitly set value to the empty string "" and then use :not?

_.each($(select).find('option'), function(option) {
    if (optionVal = $(option).val()) {

Please excuse my usage of _.each instead of jQuery's each, we'd rather stay consistent as we use underscore for lots more than just iterating over jQuery matched sets.

Answer 1

Off the top of my head, you could use either:

$(select).find('option[value!=""]');

or

$(select).find('option:not([value=""])');

to return the options that are not <option value="">All</option>

If the first option is always the valueless option, you could also use:

$(select).find('option:not(:eq(0))')

to select all option elements that are not the first-child .

Answer 2

If you want to exclude the first Option from every Select element, you can use :not() selector and .find() method:

$('select').find('option:not(:first)');  

In case that you want to filter the Options that have value, you can use .filter() method:

$('select option').filter(function() {
   return $.trim(this.value).length;
});

Note for iterating through jQuery collections it's better to use jQuery's .each() method, otherwise you will lose the chainabilty that jQuery provides.

Answer 3

$(select).find('option[value]'); // selects all <option>s with value

如果我没有正确理解这个问题。

Answer 4

You may try this

HTML:

<select>
    <option>All</option>
    <option value>0</option>
    <option value=1>One</option>
    <option value=2>Two</option>
</select>

JS: This will return only last two options (One and Two)

$('select option').filter(function(){
    return this.hasAttribute('value') && this.value.length;
});

to filter the options for missing/null/undefined value. Here is an example .