Refering to variable loadVar dynamically

hi guys, I am reading a file with certain user defined variables like
&x=30&y=50&z=100

Lets the variable is caught in a function as argument myVar

now depending on the variable the user passes I need to fetch the value. ie if the user passes x i need to read the value of x.
Also keep in mind i dont have any idea how the user has named his/her variables.

What i need to do it get the value of that variable by using loadVar.

this.myVar;
As such it gives me undefined. There is text present in ‘this’ myVar represents ‘x’
I have tried eval(this.myVar) as well as this.eval(myVar) but in vain

How can i achieve this ?:q: