dynamically change background image with listbox

var oEditor = FCKeditorAPI.GetInstance('FCKeditor1') ;

if (oEditor!=null) { 
alert("NOT NULL"); } 
if (oEditor==null) { 
alert("NULL"); } 

oEditor.EditorDocument.body.style.cssText += 'color: #322805; background-color: #F7C928;' ;
} 

function update_picture(newimage) { 
        
var oEditor = FCKeditorAPI.GetInstance('FCKeditor1') ;
if (oEditor!=null) { 
    oEditor.EditorDocument.body.style.cssText = 'margin:0;' +
    'border:0;' +
    'background-color:transparent;' +
    'background-image:url(http://localhost/cpanel/editor/userfiles/image/entete/general_entete.gif);' ;
    alert(path);} 
if (oEditor==null) { 
    alert("NULL"); } 
  } 

function update_picture(newimage) { 
    var oEditor = FCKeditorAPI.GetInstance('FCKeditor1') ;
    var path = "http://localhost/cpanel/editor/userfiles/image/entete/" + newimage;
    if (oEditor!=null) { 
        oEditor.EditorDocument.body.style.cssText += 'color: #322805; background-image: url(path);' ;
        alert(path);} 
     if (oEditor==null) { 
        alert("NULL"); } 
}