Convert Javascript Date to JSON string for .Net DateTime

var offset = new Date().getTimezoneOffset() / 60;

if (offset <= -10)

offset = '+' + Math.abs(offset) + '00';

else if (offset > -10 && offset < 0)

offset = '+0' + Math.abs(offset) + '00';

else if (offset == 0)

offset = '';

else if (offset > 0 && offset < 10)

offset = '-0' + offset + '00';

else if (offset >= 10)

offset = '-' + offset + '00';

var d = '\/Date(' + (new Date().getTime()) + offset + ')\/';