How to retrieve site column metadata (eg. description) via CSOM (JavaScript)
var ctx = SP.ClientContext.get_current();
var web = ctx.get_web();
var fields = web.get_fields();
var field = fields.getByTitle('Workflow Name');
ctx.load(field);
ctx.executeQueryAsync(
function() {
console.log('Description:' + field.get_description());
},
function(sender,args) {
console.log('An error occured: ' + args.get_message());
}
);