How to make an option set field read-only on Save in MS Dynamics CRM 2011, so that for the next time it will be a read-only field

Question

I am using below script to make my field read-only on CRM form while saving it. My requirement is for the first time it should be editable for user and once user select value and save the form its should be read-only for the next time. but with below script whenever I am refreshing the form field will become editable again.

function Test() { 
debugger; 
Xrm.Page.ui.controls.get("new_test").setDisabled(true); 
Xrm.Page.data.entity.attributes.get("new_test").setSubmitMode("always"); 
//Xrm.Page.getAttribute("new_test").setSubmitMode("always"); 
Xrm.Page.data.entity.save(); 
}

Answer 1

You have to do it in form onLoad not onSave. If the picklist already have value selected, then disable it.

Call this formOnLoad() method in form onLoad event.

function formOnLoad() { 
    debugger; 
    if(Xrm.Page.getAttribute("new_test").getValue() != null){
        Xrm.Page.ui.controls.get("new_test").setDisabled(true); 
    }
}