This is a great website, I always point people to this site when they need help:
http://www.supportdetails.com/
Plus, it has built-in system for sending emails. If you want to make your own but base it off of their code, most of the code for this is:
// Screen Res
if (self.screen)
{
S_RESOLUTION = screen.width + ' x ' + screen.height;
S_COLOR_DEPTH = screen.colorDepth + ' bit';
}
else if (self.java)
{
var javaobj = java.awt.Toolkit.getDefaultToolkit();
var screenobj = javaobj.getScreenSize();
S_RESOLUTION = screenobj.width + ' x ' + screenobj.height;
if (self.screen)
S_COLOR_DEPTH = screen.colorDepth + ' bit'; ;
}
// Browser size
var bsw = '';
var bsh = '';
if (window.innerWidth)
{
bsw = window.innerWidth;
bsh = window.innerHeight;
}
else if (document.documentElement)
{
bsw = document.documentElement.clientWidth;
bsh = document.documentElement.clientHeight;
}
else if (document.body)
{
bsw = document.body.clientWidth;
bsh = document.body.clientHeight;
}
if (bsw != '' && bsh != '')
{
S_BROWSER_SIZE = bsw + ' x ' + bsh;
}
// Browser Type
if (S_USE_CLIENT_FOR_BROWSER == "1")
{
var browser = $.browser.name + " " + $.browser.version;
S_BROWSER_TYPE = browser;
S_BROWSER_TYPE = S_BROWSER_TYPE.replace("msie", "Internet Explorer");
if (S_BROWSER_TYPE.length > 0)
{
S_BROWSER_TYPE = S_BROWSER_TYPE.substring(0, 1).toUpperCase() + S_BROWSER_TYPE.substring(1, S_BROWSER_TYPE.length);
}
S_BROWSER_VERSION = "";
}