title: Why can't I retain this selection box's value? ([ ] brackets in select box name and ID)
body: <p>Please bear with me, my apologies if this post is too long...</p>
  
  <p>I'm attempting to build a custom advanced search form within Magento. Basically, I have a bunch of select boxes and the selected values correspond with my Magento product attribute values and append to the URL, so if you had a selection box like this:</p>
  
  <pre><code>&lt;select name="diameterange" id="diameterange"&gt;
  
        &lt;option value=''&lt;?php echo $_SESSION['post']['diameterange']=='all'?'selected="selected"':''; ?&gt;&gt;all&lt;/option&gt;
        &lt;option value='15'&lt;?php echo $_SESSION['post']['diameterange']=='15'?'selected="selected"':''; ?&gt;&gt;Small&lt;/option&gt;
        &lt;option value='14'&lt;?php echo $_SESSION['post']['diameterange']=='14'?'selected="selected"':''; ?&gt;&gt;Medium&lt;/option&gt;
        &lt;option value='13'&lt;?php echo $_SESSION['post']['diameterange']=='13'?'selected="selected"':''; ?&gt;&gt;Large&lt;/option&gt;
  </code></pre>
  
  <p></p>
  
  <p>And you chose "Small", the URL would result in:</p>
  
  <p><code>http://mymagento.com/catalogsearch/advancedsearch/result/?diameterange=15</code></p>
  
  <p>You can see I'm echoing the values so that when the results page is loaded, the user sees the same search form with their selections pre-selected, above their new search results. This all works fine and dandy except for one attribute in particular - <code>price[from]</code>.</p>
  
  <p>Here is the code for my <code>price[from]</code> selection box:</p>
  
  <pre><code>&lt;select name="price[from]" id="price[from]"&gt;
  
        &lt;option value=''&lt;?php echo $_SESSION['post']['price[from]']==''?'selected="selected"':''; ?&gt;&gt;from (all)&lt;/option&gt;
  
        &lt;option value='100'&lt;?php echo $_SESSION['post']['price[from]']=='100'?'selected="selected"':''; ?&gt;&gt;from $100&lt;/option&gt;
  
        &lt;option value='200'&lt;?php echo $_SESSION['post']['price[from]']=='200'?'selected="selected"':''; ?&gt;&gt;from $200&lt;/option&gt;
  
        &lt;option value='300'&lt;?php echo $_SESSION['post']['price[from]']=='300'?'selected="selected"':''; ?&gt;&gt;from $300&lt;/option&gt;
  
        &lt;option value='400'&lt;?php echo $_SESSION['post']['price[from]']=='400'?'selected="selected"':''; ?&gt;&gt;from $400&lt;/option&gt;
  
        &lt;option value='500'&lt;?php echo $_SESSION['post']['price[from]']=='500'?'selected="selected"':''; ?&gt;&gt;from $500&lt;/option&gt;
  
        &lt;option value='600'&lt;?php echo $_SESSION['post']['price[from]']=='600'?'selected="selected"':''; ?&gt;&gt;from $600&lt;/option&gt;
  
        &lt;option value='700'&lt;?php echo $_SESSION['post']['price[from]']=='700'?'selected="selected"':''; ?&gt;&gt;from $700+&lt;/option&gt;
  
    &lt;/select&gt;
  </code></pre>
  
  <p>This box and its selected value works correctly as far as the URL appending goes, and it will bring you the correct results, but I cannot get this selection box to remember its value like I can with the other attributes. So if a user has chosen a value in this box, his choice isn't pre-selected on the search form on the search results page.</p>
  
  <p>I'm convinced this has something to do with the [ ] brackets in the select box's name and ID. How can I echo the selected choice for this particular box?</p>
  
  <p>Thank you</p>