ssjs-try-catch-ampscript-example.html

<script runat="server">
Platform.Load("Core","1.1.1");
try{
</script>

 %%[
 set @email = emailaddr
 if (@email != "") then
   set @rows = LookupRows("LeadDataExtension","Email", @email)
   set @rowCount = rowcount(@rows)
   if @rowCount > 0 then 
     set @row = Row(@rows, 1)
     set @FirstName = Field(@row,"FirstName")
   endif
 endif
 ]%%

<script runat="server">
  }catch (e) {
          Write("<b>Error Message:</b> " + Stringify(e.message) + "<br><br><b>Description:</b> " + Stringify(e.description));
  }
</script>

Hello %%=v(@FirstName)=%%!

One note: if you want to store the error message in an error log DE, you can add this after Write:

var targetDE = 'xxxxxxx-xxxxxxx-xxxxxxxxx'; //pass external key of the target DE
var logDE = DataExtension.Init(targetDE);
var errorMsg = Stringify(e.message)
logDE.Rows.Add({ Error: errorMsg });