所有JSON.parse实现最有可能使用eval()JSON.parse基于Douglas Crockford的解决方案,该解决方案eval()在497行使用。// In the third stage we use the eval function to compile the text into a// JavaScript structure. The '{' operator is subject to a syntactic ambiguity// in JavaScript: it can begin a block or an object literal. We wrap the text// in parens to eliminate the ambiguity.j = eval('(' + text + ')');的优点JSON.parse是它可以验证参数是否为正确的JSON语法。