PowerShell 2.0 ConvertFrom-Json and ConvertTo-Json implementation

function ConvertTo-Json20([object] $item){
    add-type -assembly system.web.extensions
    $ps_js=new-object system.web.script.serialization.javascriptSerializer
    return $ps_js.Serialize($item)
}

function ConvertFrom-Json20([object] $item){ 
    add-type -assembly system.web.extensions
    $ps_js=new-object system.web.script.serialization.javascriptSerializer

    #The comma operator is the array construction operator in PowerShell
    return ,$ps_js.DeserializeObject($item)
}

If you're getting the error:

Add-Type : Could not load file or assembly 'System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35 or one of its dependencies. The system cannot find the file specified. "

... these registry commands can be run (more details):

   reg add hklm\software\microsoft\.netframework /v OnlyUseLatestCLR /t REG_DWORD /d 1 /f
   reg add hklm\software\wow6432node\microsoft\.netframework /v OnlyUseLatestCLR /t REG_DWORD /d 1 /f