1.模仿jquery each
function each(obj, fn){ var i; if(Object.prototype.toString.call(obj) === '[object Array]'){ for(i = 0, length = obj.length; i < length; i++){ fn.call(obj[i], i, obj[i]); } } else if(typeof obj === 'object'){ for(i in obj){ if(obj.hasOwnProperty(i)){ fn.call(obj[i], i, obj[i]); } } } else{ return false; } }