javascript eval和JSON之间的联系

var bar = ‘bar‘;
var foobar = eval(‘"foo" + bar‘);
alert(foobar);

eval评估JavaScript语句

var bar = ‘bar‘;
// if variable bar equals ‘bar‘, foobar is the result of 
// last executing statement: bar="foo-bar";
var foobar = eval(‘if(bar == "bar") {bar="foo-bar";} else {bar = "bar-foo";}‘);
alert(foobar);// change the valuebar = ‘foo‘;
// now our the last executed statement is: bar = "bar-foo";
// therefore the value of variable foobar has been changed
// into ‘bar-foo‘
foobar = eval(‘if(bar == "bar") {bar="foo-bar";} else {bar = "bar-foo";}‘);
alert(foobar);

JSON的格式

var objectLiteral = {
  name: "Objector.L",
  age: "24",
  special: "JavaScript",
  sayName: function() {
    return this.name;
  }
};

JSON对象

var jsonFormat = {
  "summary": "Blogs",
  "blogrolls": [
    {
       "title": "Explore JavaScript",
       "link": "http://example.com/"
    },
    { 
       "title": "Explore JavaScript",
       "link": "http://example.com/"
    }
  ]
};

var jsonObject = eval("(" + jsonFormat + ")");

alert(eval("{}"); // return undefined
alert(eval("({})");// return object[Object]

alert(eval(‘{foo:"bar"}‘));   // return "bar", incorrect

eval正确解析JSON

alert(eval(‘({"foo": "bar"})‘)); // return JSON object, correct

eval(‘(‘ + jsonString + ‘)‘);