input type="hidden" value="....a chain of rubbish letter....

[tong123123]

I use the browser view source function to see 
the html generated by jsf, 
and always see something like the following:

<input type="hidden" name="javax.faces.ViewState" id="javax.faces.ViewState" 
value="8EgC7hvJoXWgMHaUZxk5rx66APlnNueyP32ajDxbvc
/i5akMf2jX5ZGyBjrnsmcbFDLXCaS8cHN169OeG5k
DXxvWNcBMTAigJiokZI5Ne66G0/CILkEquml3xSn
+jI4+HDkEeDEBtmlPDjjFJyOcOmZ+87klHuSTgAe
5P6mMDOQOqrH0Pj9yl+
............++nBOnItypO1I+XXANTsWVuCGc
V2sghVuKD42Kt/UFL7c6gh4S7KuRSQTuzsQzs
kJZBO7OxDOyQl0Yq1NF68G0U6T4uIj27tlXp
OehNZq4LNOhvQdQH7D6ZKdmAKbVesQLrzhzo
9mnY9MN0zJj1r9NhEWfhlFpRxIxYKVda+2p
PzvUD9+wbS2NpmjNu5opnJ++XI9z5KpWbdb
lb9JKIaP6Zzxdsh2E41VBicsyuBzaOTZoz
buaKZyfvJAmuJTdCe+/H9z8iOGr8SQHtmk1
8OUgs7l4BGSVeW3JGgo6F2EHIjEMwkhmgQI
kRwDYBkboU2tAin0sPxMybTF65p98Jrn1Gs
......10bBgnfB2FWSo74DqQ==" />

the value is a chain of meaningless letter, what is it? 
will it slow down the page rendering in browser?



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