dmi,
<script>
var json = [
{"Itemid":35,
"name":"test",
"hide":0
},
{"Itemid":36,
"name":"test22",
"hide":0
},
{"Itemid":37,
"name":"test33",
"hide":0
},
{"Itemid":38,
"name":"test32",
"hide":0
}
], arr = [{"Itemid":39,
"name":"test44",
"hide":0
},
{"Itemid":40,
"name":"test55",
"hide":0
}]
json.some(function(a) {
return a.Itemid == 37 && (a.parent = arr)
})
document.write(JSON.stringify(json))
</script>