capitalize first charcter sentence

Add the following code to the custom validation script of the field. The code will split the paragraph into sentences as long as the separator is a period followed by at least one space. It then strips and leading spaces in case people double space after a period (yuck) and then converts the first character to uppercase... it doesn't bother to check. It then reassembles the sentences into a paragraph where the sentences are separated by a period and a single space.

The conversion happens when the user exits the field just prior to committing the value.

var para = event.value; 
var sentences = para.split(". "); 
for (var i=0; i < sentences.length; i++) {
     sentences = sentences.trim().charAt(0).toUpperCase() + sentences.slice(1); 
}
event.rc = true;
event.value = sentences.join(". ");