p_key is NULL the snippet is always added.
Table 14-9 ADD_ONLOAD_CODE Parameters
Any name to identify the specified code snippet. If specified, the code snippet is added if there has been no other call with the same
initMySuperWidget()to the onload buffer. If the plug-in is used multiple times on the page and the
add_onload_code is called multiple times, it is added once to the HTML output because all calls have the same value for