You need core.js loaded before _spBodyOnLoadFunctionNames can work, make sure its loaded bedore running your script. _spBodyOnLoadFunctionNames is an array, that are execute in the ProcessOnLoadFunctionNames function. The ProcessOnLoadFunctionNames is executed in the ProcessDefaultOnLoad function. The ProcessDefaultOnLoad is execute with: ExecuteOrDelayUntilScriptLoaded(ProcessDefaultOnLoad, "core.js");

You could also use ExecuteOrDelayUntilBodyLoaded(FunctionName()); or ExecuteOrDelayUntilScriptLoaded(FunctionName, "core.js");

You need init.js loaded before _spBodyOnLoadFunctionNames can work, make sure its loaded before running your script. _spBodyOnLoadFunctionNames is an array, that are execute in the ProcessOnLoadFunctionNames function. The ProcessOnLoadFunctionNames is executed in the ProcessDefaultOnLoad function. The ProcessDefaultOnLoad is execute with: ExecuteOrDelayUntilScriptLoaded(ProcessDefaultOnLoad, "core.js");

You could also use ExecuteOrDelayUntilBodyLoaded(FunctionName()); or ExecuteOrDelayUntilScriptLoaded(FunctionName, "core.js");