Getting the size of an array in an object
Solution 1:
Javascript arrays have a length property. Use it like this:
st.itemb.length
Solution 2:
Arrays have a property .length that returns the number of elements.
var st =
{
"itema":{},
"itemb":
[
{"id":"s01","cd":"c01","dd":"d01"},
{"id":"s02","cd":"c02","dd":"d02"}
]
};
st.itemb.length // 2