便利数组情况的json

var ddd = {
"demo": [
    { 
        "firstName1":"11" , "lastName1":"12"
         },
    { 
        "firstName1":"21" , "lastName1":"22"
         },
    { 
        "firstName3":"31" , "lastName3":"32"
         },
    { 
        "firstName4":"41" , "lastName4":"42" 
    }
  ]
}

json

$.each(ddd["demo"], function(index, val) {
 
    console.log(ddd.demo[index].firstName1)  

});