JavaScript eval

eval() is a global function in JavaScript that evaluates a specified string as JavaScript code and executes it.

eval("alert('this is executed by eval()')");

The eval() function can also call the function and get the result as shown below.

var result;
function Sum(val1, val2)
{
                        return val1 + val2;
}
eval("result = Sum(5, 5);");
alert(result);

eval can convert string to JSON object.

var str = '({"firstName":"Bill","lastName":"Gates"})';
var obj = eval(str);
obj.firstName; // Bill