Simple JSON path parser

data.js

// Source data (JSON) from the server
data = {
    abc: {
        def: {
            ghi: 'jkl'
        }
    }
};

// The path you're looking for (you want the value of `ghi`)
path = 'abc.def.ghi';

path.js

// Break up the path into properties
parts = path.split('.');

// Get the name of the value
// Note that `.pop` will alter the array so `parts` now only contains `['abc', 'def']`
valueName = parts.pop();

// This will hold your value. Start by assigning to the data object as a whole
value = data;

// Loop through `parts` to drill deeper into the data
parts.forEach(function(part) {
    // Replace the current property with the next (one level deeper) property
    value = value[part];
});

// Now that we've gone through the parts of the path, we're at the last property/object, `def`. The only thing left is to get the value:
value = value[valueName];

// Now `value = 'jkl'`