JAVASCRIPT ARRAY COMPARISON with dropdownlist selected vlue

function checkvalue() {

var k = [{ "ModelId": 1095, "ModelName": "paste", "UnitCost": 25.0000 }, { "ModelId": 1175, "ModelName": "ffffff ", "UnitCost": 567892.0000}];

var j = $('#dropdownid').val();

for (var i = 0; i < k.length; i++) {

if (j == k[i].ModelId) {

alert(k[i].UnitCost);

break;

}

}

}