Here a JScript variant of JohnB's answer
// Below the MSDN page for MapNetworkDrive Method with link and in case if Microsoft breaks it like every now and then the path to the documentation of now.
// https://msdn.microsoft.com/en-us/library/8kst88h6(v=vs.84).aspx
// MSDN Library -> Web Development -> Scripting -> JScript and VBScript -> Windows Scripting -> Windows Script Host -> Reference (Windows Script Host) -> Methods (Windows Script Host) -> MapNetworkDrive Method
var WshNetwork = WScript.CreateObject('WScript.Network');
function localNameInUse(localName) {
var driveIterator = WshNetwork.EnumNetworkDrives();
for (var i=0, l=driveIterator.length; i < l; i += 2) {
if (driveIterator.Item(i) == localName) {
return true;
}
}
return false;
}
function mount(localName, remoteName) {
if (localNameInUse(localName)) {
WScript.Echo('"' + localName + '" drive letter already in use.');
} else {
WshNetwork.MapNetworkDrive(localName, remoteName);
}
}
function unmount(localName) {
if (localNameInUse(localName)) {
WshNetwork.RemoveNetworkDrive(localName);
}
}