diff --git a/src/utils/string.js b/src/utils/string.js
new file mode 100644
index 0000000..92a860e
--- /dev/null
+++ b/src/utils/string.js
@@ -0,0 +1,56 @@
+// 比较日期，时间大小
+export function compareCalendar(t1, t2) {
+  if (t1.indexOf(' ') !== -1 && t2.indexOf(' ') !== -1) {
+    // 包含时间，日期
+    return compareTime(t1, t2)
+  } else {
+    // 不包含时间，只包含日期
+    return compareDate(t1, t2)
+  }
+}
+
+// 比较日期大小
+function compareDate(logintime, logouttime) {
+  var arys1 = []
+  var arys2 = []
+  if (logintime != null && logouttime != null) {
+    arys1 = logintime.split('-')
+    var logindate = new Date(arys1[0], parseInt(arys1[1] - 1), arys1[2])
+    arys2 = logouttime.split('-')
+    var logoutdate = new Date(arys2[0], parseInt(arys2[1] - 1), arys2[2])
+    if (logindate > logoutdate) {
+      return -1
+    } else if (logindate === logoutdate) {
+      return 0
+    } else {
+      return 1
+    }
+  }
+}
+
+// 判断日期，时间大小
+function compareTime(logintime, logouttime) {
+  if (logintime.length > 0 && logouttime.length > 0) {
+    var logintimeTemp = logintime.split(' ')
+    var logouttimeTemp = logouttime.split(' ')
+
+    var arrloginDate = logintimeTemp[0].split('-')
+    var arrlogoutDate = logouttimeTemp[0].split('-')
+
+    var arrloginTime = logintimeTemp[1].split(':')
+    var arrlogoutTime = logouttimeTemp[1].split(':')
+
+    var allLoginDate = new Date(arrloginDate[0], arrloginDate[1], arrloginDate[2], arrloginTime[0], arrloginTime[1], arrloginTime[2])
+    var allLogoutDate = new Date(arrlogoutDate[0], arrlogoutDate[1], arrlogoutDate[2], arrlogoutTime[0], arrlogoutTime[1], arrlogoutTime[2])
+
+    if (allLoginDate.getTime() > allLogoutDate.getTime()) {
+      return -1
+    } else if (allLoginDate.getTime() === allLogoutDate.getTime()) {
+      return 0
+    } else {
+      return 1
+    }
+  } else {
+    return -1
+  }
+}