An unexpected newline appears when use memc and echo location async, how to delete the newline?

Server NGINX
1

I use the agenzh’s two modules

*nginx configuration:
*
location ~ “^/property/([0-9]+)” {
charset utf-8;
default_type ‘text/javascript’;
echo -n “$arg_callback({"property_$1":"”;
echo_location_async /statistic/operator
“cmd=incr&key=property_$1&value=1”;
echo -n “")”;
}

# GET /statistic/operator?cmd=incr&key=property_23214&value=2
# GET /statistic/operator?cmd=decr&key=property_23214&value=1
location /statistic/operator {
    internal;
    set $memc_cmd $arg_cmd;
    set $memc_key $arg_key;
    set $memc_value $arg_value;
    memc_pass statistics_server_pool;
    memc_cmds_allowed incr decr set get delete add;
    add_header X-Memc-Flags 'Statistic Crement';
}

*Request URL:
*
http://domain.net/property/23458?hi=231231&callback=himycallback201203455

The Unexpected incorrect Output: (Current Configuration)

himycallback201203455({“property_23458”:24
})

The new line after 24 is unexpected. and how can l delete the new line ?

I expected the correct Output: ( how to configuration the nginx ? )

himycallback201203455({“property_23458”:24})