Wanting to auto-populate initials in a field based on the first of each word in another field.

Use script as validation script of "Name Field" and replace "Signature" field names to your actual field names and add more/less fields as needed:

var str = event.value;

if(event.value == ""){
this.getField("Signature1").value = "";
this.getField("Signature2").value = "";
this.getField("Signature3").value = "";}
else{
var r = str.split(" ");
var y = r[0].substr(0, 1)+r[1].substr(0, 1);
this.getField("Signature1").value = y;
this.getField("Signature2").value = y;
this.getField("Signature3").value = y;}