How can I get value in config_override.php via js

I don't think this is possible out of the box (although I have a workaround below) for security reasons. The values in config/config_override include stuff like database connection details, which you might not even want your highest privileged application users (i.e. Administrators) to know. The way I'd implement this is by creating a custom endpoint:

http://support.sugarcrm.com/Documentation/Sugar_Developer/Sugar_Developer_Guide_7.6/API/Web_Services/Extending_Web_Servi…

The main change I'd make to the endpoint api in the example is:

 public function MyGetMethod($api, $args){
  global $sugarconfig;
  return $sugarconfig['custom_value'];
  }

You could then get the value using the loadData function in your controller like this:

loadData: function () {
        var _this = this;
        App.api.call('GET', App.api.buildURL('name_of_your_endpoint', null, null, ''), null, {
            success: function (custom_value) {
                _this.custom_value = custom_value;
                _this.render();
            }}
        );
    },

Let me know if you have any trouble with this method.

I don't think this is possible out of the box (although I have a workaround below) for security reasons. The values in config/config_override include stuff like database connection details, which you might not even want your highest privileged application users (i.e. Administrators) to know. The way I'd implement this is by creating a custom endpoint:

http://support.sugarcrm.com/Documentation/Sugar_Developer/Sugar_Developer_Guide_7.6/API/Web_Services/Extending_Web_Servi…

The main change I'd make to the endpoint api in the example is:

 public function MyGetMethod($api, $args){
  global $sugarconfig;
  return $sugarconfig['custom_value'];
  }

You could then get the value using the loadData function in your controller like this:

loadData: function () {
        var _this = this;
        App.api.call('GET', App.api.buildURL('name_of_your_endpoint', null, null, ''), null, {
            success: function (custom_value) {
                _this.custom_value = custom_value;
                _this.render();
            }}
        );
    },

Let me know if you have any trouble with this method.