I made an ajax request that saves my data that I want to send
 to the pos receipt; I want that when saving this data is also sent to the receipt for printing; 
this way it doesn't work
confirm: function() {
    var order = self.pos.get_order();
    //console.log(order.get_amount())
    var client_name=$("#client_name").text()
    var numero_agent=$("#numero_agent").text()
    var ref=document.getElementsByName("ref")[0].value
    var montant=document.getElementsByName("montant")[0].value
    if(ref != '' && montant != ''){
        console.log('dans mobile money')
        ajax.jsonRpc("http://localhost:8070/postmobilemoney/",'call',{
            name:"test",
            reference:ref,
            montant:montant,
            nom_client:client_name,
            numero_agent:numero_agent,
    }).then(function (result){
            montant=result['montant']
            ref=result['reference']
            client_name=result['nom_client']
            numero_agent=result['numero_agent']
            self.gui.show_screen('receipt',{'montant':montant,ref:'ref','client_name':client_name})
    
    })
    }else {
        alert("veuillez remplir tous les champs")
    }
},