Event.observe( window, 'load', function(){
    
    expandable_headings = $$( '.detail .long_desc h3')
    
    expandable_headings.each( function( expandable_heading){
    	
    	expandable_heading.observe( 'click', function(){
    		
    		if (this.next().visible()) {
                this.select( 'img').first().writeAttribute( 'src', '/images/plus.png')
    		} else {
                this.select( 'img').first().writeAttribute( 'src', '/images/minus.png')
    		}
    		
            Effect.toggle( this.next(), 'blind')
            
    	})
    	
    })
    
})