The Eval function requires parentheses to process JSON data

The Eval function is often used when converting a server-side built-in JSON data into a usable JavaScript object. As follows:

var datajson = eval (' (' + data + ') ');

You need to wrap a layer of parentheses around the outside of the JSON string when converting, because:
The purpose of the parentheses is to force the Eval function to force the expression in parentheses to be converted to an object while processing the JavaScript code, rather than being executed as a statement (statement). For example, if the object literal {} is not enclosed, then eval will recognize the curly brace as the start and end tag of the JavaScript block, and {} will be considered an empty statement. So the following two execution results are different:

Alert (eval ("{}");  // return undefinedalert (eval ("({})");   return Object[object]

The Eval function requires parentheses to process JSON data