gistfile1.js

// TODO: perhaps change most/all live previews to inherit from this?
LivePreview = Class.create({
  
  initialize: function(preview_fields) {
    
    preview_fields.each(function(field_id) {
      
      var field = $(field_id)
      var div   = $(field_id + "_preview");

      if (div) {
        this.bind_update(div, field);
      }
      
    }.bind(this));
    
  },
  
  bind_update: function(div, field, property) {
    
    if (!property) property = "innerHTML";
    
    div = $(div); field = $(field);
    
    field.observe("keyup", function() { this.update_property(div, field, property); }.bind(this));
    this.update_property(div, field, property);
    
  },
  
  update_property: function(div, field, prop) {
    
    if (!prop || prop == "innerHTML") {
    
      return div.update($F(field));
    
    } else {
      
      return eval("div." + prop + " = '" + $F(field).replace('"', """) + "'");
      
    }
    
  }
  
});