help the relationship between <span class> and jquery

help the relationship between <span class> and jquery

I got some code as following

<font size="3"><label>Version:<SPAN class="json_cmd" style= "display:none">{'variable': 1, 'task': 'TESTER', 'name': 'testerVer', 'value': "0.0.0.1", 'attributes': ""  }</SPAN></label></font>


it looks I am able to use element with class=json_comd as following
$(".json_cmd")
my question is what about "  {'variable': 1, 'task': 'TESTER', 'name': 'tseterVer', 'value': "0.0.0.1", 'attributes': ""  } " , is there any idea what this is ?



Many Thanks
KevinSK ...