Autoselect SERIE depends on company

I have 4 companies,
and i want the application autoselect SERIE depends on company on my DOCTYPES

for quotation
Company1 : 1QTN-
Company2 : 2QTN-
Company3 : 3QTN-
Company4 : 4QTN-

How to ?

I test this solution

cur_frm.cscript.onload_post_render = function(frm,dt,dn){

if(doc.company == ‘Company1’){
cur_frm.set_value(“naming_series”,“1QTN-”)
}else if(doc.company == ‘Company 2’){
cur_frm.set_value(“naming_series”,“2QTN-”)
}else if(doc.company == ‘Company 3’){
cur_frm.set_value(“naming_series”,“3QTN-”)
}else if(doc.company == ‘Company 4’){
cur_frm.set_value(“naming_series”,“4QTN-”)
}
}

It doesn’t work !

Can you help me please !!!

function(doc, dt, dn)