判断input的值是否是正确的日期格式yyyymmdd

//校验日期function isDate(obj){var value=obj.value;if(value!=""){year=value.substr(0,4);month=value.substr(4,2);day=value.substr(6,2);tDateString = year + '/'+month + '/'+day+' 8:0:0';dDate=new Date(tDateString);if (((dDate.getUTCFullYear()).toString()!=year) || (dDate.getMonth()!=parseInt(month,10)-1) || (dDate.getDate()!=parseInt(day,10))){obj.focus();alert("不是正确的日期类型！");return false;}}return true;}