/**
 * Usage:   new SNExpander(title, holderID, contentElementId);
 *
 *  {title}                 What the button's text should say
 *  {holderID}              An empty div put where ever you want the button made
 *  {contentElementId}      Id of element we want hidden/shown by this expander
 *
 *
 * example:
 *
 * [+] Titre     --------- click -------->         [-] Titre
 *                                                   ____________________
 *                                                  |                    |
 *                                                  |                    |
 *                                                  |  contentElementId  |
 *                                                  |                    |
 *                                                  |                    |
 *                                                   ____________________
 *
 *                                                  *holderID is the Div
 *                                                  *that Titre is in
 *  
 */      
function SNExpander(t, hID, cID)
{

    var me = this;
    var titre = t;
    var contenu, ancre, imgplus;
    init();
    
    
    
    function init()
    {
        if (!document.getElementById(cID)) return;
        contenu = document.getElementById(cID);
        if (!document.getElementById(hID)) return;
        var holder = document.getElementById(hID);
        ancre = document.createElement("div");
        holder.appendChild(ancre);
        imgplus = new Image();
        imgplus.src = "http://media.supernova.com/images/accordion-plussign.gif";
        imgplus.className = "sn_ExpandableNodeSign";
        ancre.appendChild(imgplus);
        var txtfld = document.createTextNode(titre);
        ancre.appendChild(txtfld);
        ancre.className = "sn_ExpandableNode";
        ancre.onclick = function(){me.manageExpansion();}
        contenu.style.display = "none";
        initStretch();
    }


    this.manageExpansion = function()
    {
        var b = imgplus.src.match(/plus/ig)!=null;
        imgplus.src = imgplus.src.replace(b?"plus":"minus",b?"minus":"plus");
        contenu.style.display = b ? "block" : "none";
        initStretch();
    }
    
    


}