XML scripting uses UJML-specified XML scripting elements inside of an execute element. See execute. These same XML scripting elements may be used to specify expressions inside of other UJML elements which contain data values. See Expressions. 

Script blocks using the script element are the preferred method of scripting in UJML. See Script Blocks, script. This is partly because XML scripting is different from other languages while script blocks are more familiar to experienced programmers. Also XML scripts tend to be verbose and difficult to read and XML scripting is no longer in active development, while script blocks are being extended with new features. 

However, XML scripting has advantages in certain situations and is retained in UJML for those purposes. These include the fact that string literals in XML scripts do not require quotes and may easily contain quotes and special characters, and the fact that XML scripting works well with UJML generating template-based systems like Java Server Pages (JSP). If you are having problems with script blocks in those scenarios, you may wish to try XML scripting.

Expressions, <execute>, Script Blocks, <script>