Removing matched options from a select menu with javascript

StackOverflow https://stackoverflow.com/questions/19999673

  •  30-07-2022
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Question

I have a select menu of countries (I can't change this server side). One of its options is already selected, based on previous user choice.

I also have a list of country codes (also generated server side) which specifies the countries that should appear in the menu. (Most should be removed.)

I have come up with the following script, and can't see why it doesn't work. I can disable the unwanted countries with 

  countrymenu.options[i].disabled = true;

but

  countrymenu.remove[i];

(which is what I need) does nothing.

Any help would be appreciated.

<html>
    <head>
        <script type="text/javascript">
            function HideCountries()
            {
                countrymenu = document.checkoutform.country_code;

                for (var i = 0; i < countrymenu.length; i++)
                { 
                    if (/^ASM|AIA$/.test(countrymenu.options[i].value)==false) 
                    {
                        countrymenu.remove[i];
                    }
                }
            }

            window.onload=HideCountries;
        </script>
    </head>
    <body>
        <form name="checkoutform">
            <select name="country_code"  id="country_code">
                <option value="AFG">Afghanistan</option>
                <option value="ALA">&Aring;land Is.</option>
                <option value="ALB">Albania</option>
                <option value="DZA">Algeria</option>
                <option value="ASM">American Samoa</option>
                <option value="AND">Andorra</option>
                <option value="AGO">Angola</option>
                <option value="AIA">Anguilla</option>
                <option value="ATA" selected="selected">Antarctica</option>
            </select>       
            <input type="submit" />
        </form>
    </body>
</html>
Was it helpful?

Solution

Although you have the remove() function incorrect, you should also remove items in reverse order, because once an item is removed, indices are shifted.

http://jsfiddle.net/MrPolywhirl/gPY3p/

function hideCountries() {
    countrymenu = document.getElementsByName('country_code')[0]
    for (var i = countrymenu.length-1; i >= 0; i--) {
        if (/^ASM|AIA$/.test(countrymenu.options[i].value) == false) {
            countrymenu.remove(i);
        }
    }
}

window.onload = hideCountries();

This should leave only:

  • American Samoa
  • Anguilla

OTHER TIPS

remove is a function. It is called with regular parentheses.

countrymenu.remove(i);

remove[i] tries to use the function as an array. This fails, so nothing happens. Also it may cause an error that stops the code.

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