Dec 082012

In a previous post of the series on Google maps we have seen how to add markers to the map to annotate specific points in it.

Sometimes, we would like to highlight an area on the map, rather than a single point. Using the Google Maps API it is also possible to highlight an area on the map defined by means of a single polygon or a set or polygons.

Finally, if we want to highlight a path, it is also possible to do it by means of a polyline.

In this post we will explain how to highlight areas and paths on the map with Google Maps API V3, with usage examples.

Continue reading »

 Posted by at 9:28 am
Dec 012012

This post continues the series started in our post on adding a map from Google Maps to a web page. Here we will explain how to work dynamically with the map, using javascript to modify its characteristics (center point, zoom level, etc…), and handling events generated in the map (when the user clicks on it, or pans/zooms the map).

Continue reading »

 Posted by at 5:27 pm
Nov 032012

For every type of event that can be generated in a web page (i.e., hovering the cursor over an element, pressing a key, clicking with the mouse, etc.) it is possible to associate a javascript function as an event handler. But, when there are two overlapped elements, and both of them have event handlers for the same type of event, we may wonder which of these handlers is executed first. In this post we will review the existing possibilities and how to control the propagation of events from outer to inner elements and viceversa.

Continue reading »

 Posted by at 9:29 pm
Aug 122012

jQuery is a javascript library that gives the programmer the ability to perform changes to the content of a web page in an easy and cross-browser way. Besides, jQuery offers as well an easy interface for:

  • javascript event management
  • Animations
  • Ajax interactions (dynamic loading of content)

jQuery is the library of choice for some of the most relevant sites, such as,,, or

In this post we will comment the main characteristics of jQuery and how to make use of it.

Continue reading »

 Posted by at 7:03 am
Jul 052012

In this post we will show how to set up in our web page a drawing area where the user can draw using the mouse. The drawing can then be uploaded to the server to be stored as an image file (default to png format), or processed as desired.

We will make use of this functionality in our  diccionario mandarín-español. The user will be able to enter the hanzi symbol to be looked up by drawing it with the mouse. This will also require an OCR (Optical character recognition)  software with support for simplified chinese. This topic will be subject of a later post in this blog.

Continue reading »

 Posted by at 8:02 pm