This script puts hyperlinks on all the words on a web page. Clicking on one of the words causes a popup window to appear with the translation of the word. To use this feature, enter below the URL of the web page you want to read, select a translation dictionary, and click the button.
Here are some documents I recommend for native English readers learning Spanish.
I suggest reading one chapter each day. Read the chapter first in English, then in Spanish, looking up any words that you don't know. Then listen to the audio recording of the chapter, and finally play the recording again, this time reading aloud from the text as you go.
The script is currently hosted on Red Hat's OpenShift cloud service. Its source code is available in a GitHub repository.
It can be used offline (without an Internet connection), so long as you have Perl and a web server. Set the web server to execute .pl files as CGI scripts. A local Spanish-English dictionary is also required. If you have the Larousse Gran Diccionario, you can copy (or link) its data directory into the script's perl directory, and it will become available as "local Larousse".