Extract word from string using jquery or javascript

I would like to extract word from tag like

<li>{firstname} {last name}</li>

So, can I get extract strings "firstname" and "last name" using javascipt or jquery?

Actually I think I have made some mistake to explain.

my String looks like

<li><a href="#contactDetail">{firstname} {lastname}</a></li>

here i would like to know how many parameters available means {first..} {last...} that can be only {fi..} and I would like replace with some other parameters.

So, I have a list of array which includes many parameters like firstname, lastname, address and so on... now I would like to replace that with according to what i will get from string.

Hopefully, I have tried my best to explain my problem.

if the li element is part of the dom use something like:

var names = $('body ul li').text().split(' ');
var firstName = names[0];
var lastName = names[1];

You could try something like this.

http://jsfiddle.net/W5Uh6/2/

Markup

<ol id="names">
    <li>Jason Brown</li>
    <li>Danny Glover</li>
    <li>Jack Jill</li>
</ol>

JS

$(function(){
    var firstNames = [];
    var lastNames = [];

    $("#names li").each(function(){
       var text = $(this).text().split(' ');

        firstNames.push(text[0]);
        lastNames.push(text[1]);
    }); 
});

Puts each word into an array that is separated by a space. You an then grab the values from the array.