setValue of ui.dbllist, Methods Webix Docs

specifies the item(s) that should be selected

void setValue(string|array ids);

string|arraythe id (ids) of the items to select

Example

webix.ui({
    view:"dbllist", 
    id:"dbl1",
    data:[
        {id:"1", value:"Guest"},
        {id:"2", value:"Member"},
        {id:"3", value:"Moderator"},
        {id:"4", value:"Admin"},
        {id:"5", value:"Super Admin"}
    ]
});
 
$$("dbl1").setValue([1,3]); 
 
//or
$$("dbl1").setValue("1,3");

Related samples

Double List as Form Input