第一种
json.parse(jsonstring)
第二种
eval((+jsonstring+))
第三种
var obj=(function tojson(o){
if(typeof(o)=="string")try{return new function("return "+o)();}catch(e){return null;}
})("[{name:'zhangsan',age:'24'},{name:'lisi',age:'30'},{name:'wangwu',age:'16'},{name:'tianqi',age:'7'}]");
for(var b in obj)alert(obj[b].name);