Find the first letter of the last word with inside a string (string can have multiple words)

Find the first letter of the last word with inside a string (string can have multiple words)

Hy, is there a way to find the first letter of the last word in a string? The strings are results in a XML parser function. Inside the each() loop for every node i catch the string like this: var str = xml.find("name").text();

str can have multiple words:

Examples:

str = "One Two Three";

str = "Hy what's up!";

In the first example i need the letter "T"  in the second example i need the letter "u" -> those are the first letters from the last words.

TY