There are four tables related to Drupal blocks:

Eleven of the 74 core Drupal 7 tables are to support caching. Below, each of these tables are enumerated and their purpose is described:

This tutorial allows one or more donations to be made on your site. It can also be used for other types of payments where the payer specifies the amount, for example a simple invoice payment where the user enters the invoice number and amount.

1. Install the necessary modules.

• Download Commerce and install the whole profusion.
• Download and install Customizable Products
• Download and install Rules.

2. Add the donation product line item type

In File Entity 7.x-2.x, each file uploaded is automatically classified into a 'file type'. Each file type can have custom display options (for example, you might want to display 'Documents' as links to files, but 'Images' as an image preview). File types are managed at 'admin/structure/file-types'. You may edit existing file types as well as create your own.

Configure basic settings for the Node Convert module, so you can use a new "Convert" tab to switch any node to a different node type, without losing existing field data.

To add a target like _blank

1- Go to administration inside text format (admin/config/content/formats)
and choose the format you want to allow target.

2- Activate the filter HTML Purifier (advanced)

3- at bottom of option there is a tab to configure html purifier, the second option is AllowedFrameTargets
in that field add the target you want to allow in this case: _blank (check the picture attachment).

4- go bottom of the page and save change.

5- Delete cache