HOw to extract data using json

[Priti24]

i have a variable like $list having some value

$list = "res":{ "url":"http://www.astm.org/FULL_TEXT/D5447/HTML/D5447.
+htm", "title":"Standard Guide for Application of a Groundwater Flow M
+odel to a Site-Specific Problem ", "snippet":"1.1 This guide covers t
+he application and subsequent documentation of a groundwater flow mod
+el to a particular site or problem. In this context, x201C; groundwat
+er flow model x201D; refers to the application of a mathematical mode
+l to the solution of a site-specific groundwater flow problem. 1.2 Th
+is guide illustrates the major steps to take in developing a groundwa
+ter flow model that ", "meta":{"gs_designation":"D5447","mc_section":
+"04","mc_maincomm":"D18","mc_date":"2010","mc_dltype":"allstd,active"
+,"mc_doctype":"Active Standard","mc_addtocart":"PDF-D5447","mc_login"
+:"true","mc_suburl":"/SUBSCRIPTION/filtrexx40.cgi?+/usr6/htdocs/newpi
+lot.com/SUBSCRIPTION/REDLINE_PAGES/D5447.htm","mc_relatedurl":"D5447_
+related.htm","mc_keywords":" computer model~ groundwater~ simulation~
+ Ground-water model~ ICS Number Code 13.060.10 (Water of natural reso
+urces)","gs_year":"04(2010)","gs_collection":"EEE,EEE,OOO","gs_homebo
+ok":"0408 CS04" } }}

i want to extract url ,title ,date from this variable. please help me how could this be possible using JSON.