Rendering a hierarchy of “OPTION”s in a “SELECT” t

问题:

My problem is HTML and CSS related. I have a hierarchy type structure that I want to display inside a list. The hierarchy contains Countries, States and Cities (it is three levels deep).

I want to display the list inside a select list, each item type (Country, State, City) must be selectable. The items should appear indented as:

United States
- Hawaii
-- Kauai
- Washington
-- Seattle
-- Chelan

The problem is with the indentation. I am trying to use either margin-left or padding-left to indent the tags, which appear correct in FireFox but not in IE7. This is an example of the generated select list:

<select name="Something">
<option style="padding-left: 0">United States</option>
<option style="padding-left: 20px">Hawaii</option>
<option style="padding-left: 40px">Kauai</option>
<option style="padding-left: 20px">Washington</option>
<option style="padding-left: 40px">Seattle</option>
<option style="padding-left: 40px">Chelan</option>
</select>

I want to achieve consistent indentation across browsers without using CSS hacks.

回答1:

deceze way is much better and was my first idea. As an alternative if that doesn't work is that you can use non-breaking spaces in the tag value:

<select>
    <option>select me</option>
    <option>&nbsp;me indented</option>
    <option>&nbsp;&nbsp;even more indentation</option>
</select>

It's far from pretty but it might work for you if the optgroup doesn't.

回答2:

The rendering of SELECT elements is largely up to the browser, you have very little influence over their presentation. Some browsers obviously allow you more customization than others, IE happens to allow very little (gasp, who'd have thunk ;)). If you need very custom SELECT elements, you'll need to employ JavaScript or re-create something that behaves like a SELECT but is made of a bunch of DIVs and checkboxes or something to that extend.

Having said that, I think what you're looking for are OPTGROUPs:

<select>
  <optgroup label="xxx">
    <option value="xxxx">xxxx</option>
    ....
  </optgroup>
  <optgroup label="yyy">
    ...
  </optgroup>
</select>

Every browser will display them differently, but they'll be displayed in a distinctive fashion in one way or another. Note though that officially in HTML4 you can't nest OPTGROUPs.

回答3:

Just for the sake of visitors, I feel I should share this solution I devised: http://jsfiddle.net/n9qpN/

Decorate the options with the level class

<select name="hierarchiacal">
<option class="level_1">United States</option>
    <option class="level_2">Hawaii</option>
        <option class="level_3">Kauai</option>
    <option class="level_2">Washington</option>
        <option class="level_3">Seattle</option>
        <option class="level_3">Chelan</option>
</select>

We can now use jQuery to reformat the content of the select element

$(document).ready(
function(){
   $('.level_2').each(
        function(){
            $(this).text('----'+$(this).text());
        }
   );

   $('.level_3').each(
        function(){
            $(this).text('---------'+$(this).text());
        }
   );

 }
);

This can be extended to any level

回答4:

Isn't this method of grouping creating more problems than it solves? As a user, which of those am I supposed to choose? Is there any benefit to choosing something more specific than country?

If the issue is that you only have one database field to store them in, why not have three separate select boxes (making 2 or 3 optional) and just store the most specific?:

<select name="country">
    <option>Choose a country</option>
    <option>United States</option>
</select>
<select name="state">
    <option>Choose a state</option>
    <option>Hawaii</option>
</select>
<select name="city">
    <option>Choose a city</option>
    <option>Kauai</option>
</select>

回答5:

Try using  

<select name="Something">
  <option>United States</option>
  <option>&#160;Hawaii</option>
  <option>&#160;&#160;Kauai</option>
  <option>&#160;Washington</option>
  <option>&#160;&#160;Seattle</option>
  <option>&#160;&#160;Chelan</option>
</select>

回答6:

Prepending Non breaking space (&nbsp) did not work for me.

I prepended the following:

String.fromCharCode(8194);

回答7:

I was able to accomplish this using the NO-BREAK SPACE unicode character. http://www.fileformat.info/info/unicode/char/00a0/index.htm

Copy-paste the character from that page into code and voila: https://jsfiddle.net/fwillerup/r9ch988h/

(  didn't work for me because I was using a library for fancy select boxes that would inject them verbatim.)