Splitting of first name and last name

if ( sMsgCode == "NPR" && sNPRType == "EXPORT")
{
sName = this.GetFieldValue("Name");
sFstname = "";
sLstname = "";
if (sName != "")
{
sNameArray = sName.split(" ");
for (var i = 0; i < sNameArray.length-2; i++)
{
if (sNameArray[i] = "")
sFstname = sFstname + sNameArray[i] + " ";
}
sFstname = sFstname + sNameArray[i];
sLstname = sNameArray[i+1];
this.SetFieldValue("First Name",sFstname);
this.SetFieldValue("Last Name",sLstname);
}