split JSON data from PHP to three arrays in JavaScript

split JSON data from PHP to three arrays in JavaScript

I am passing values from PHP Script to JS using JSON encode.
$arr=array('X'=>$X,'Y'=>$Y,'par'=>$par);
echo json_encode($arr);
Which produces
{"X":
["-0.9537121038646844","-0.9537121038646844","-0.9537121038646844","0.9537121038646843",""],
"Y":
["-0.9537121038646844","-0.7799936811949519","-0.5533396521383813","-0.37962122946864896",null],
"par":
["0.009811016749950838","0.005007306592216437","5.058030686503405E-4","9.451402320405391E-4",null]}
In the javascript, I used the following command
{
$.post("plot.php",param,function(data){dataType:"json";console.log(data);Var
X1=data.X;});
}
But I am not able to obtain the values of X alone. I tried few suggestions
from similar threads, but none of them did the trick.I need the three
arrays, X,Y and Par to be used in JS.