diff --git a/parseQueryString.js b/parseQueryString.js
index 35e4882..7f37d8e 100644
--- a/parseQueryString.js
+++ b/parseQueryString.js
@@ -5,12 +5,28 @@
  * @return {Object} 
  */
 function parseQueryString(url) {
-    url = url == null ? window.location.href : url
-    var search = url.substring(url.lastIndexOf('?') + 1)
+    url = (!url ? window.location.href : url);
+    if(url.indexOf('?') === -1) {
+        return {};
+    }
+    var search = url.substring(url.lastIndexOf('?') + 1);
     if (!search) {
-        return {}
+        return {};
+    }
+    var data = {};
+    try{
+        data = JSON.parse(
+            '{"' +
+                decodeURIComponent(search)
+                    .replace(/"/g, '\\"')
+                    .replace(/&/g, '","')
+                    .replace(/=/g, '":"') +
+                '"}'
+        );
+    } catch (e) {
+        console.error('数据格式错误');
     }
-    return JSON.parse('{"' + decodeURIComponent(search).replace(/"/g, '\\"').replace(/&/g, '","').replace(/=/g, '":"') + '"}')
+    return data;
 }
 
-module.exports = parseQueryString
\ No newline at end of file
+module.exports = parseQueryString
diff --git a/src/dom/imgLazy.js b/src/dom/imgLazy.js
new file mode 100644
index 0000000..b427641
--- /dev/null
+++ b/src/dom/imgLazy.js
@@ -0,0 +1,19 @@
+/**
+ * @desc 图片预加载
+ * @param {String} 预加载src
+ * @return {Promise}
+ */
+function imgLazy(src) {
+  return new Promise((resolve, reject) => {
+    var img = new Image();
+    img.src = src;
+    img.onload = function() {
+      resolve(img);
+    };
+    img.onerror = function() {
+      console.error("图片加载失败", src);
+      reject(false);
+    };
+  });
+}
+module.exports = imgLazy;
\ No newline at end of file
diff --git a/src/index.js b/src/index.js
index 64b2546..aa20042 100644
--- a/src/index.js
+++ b/src/index.js
@@ -19,6 +19,7 @@ const offset = require('./dom/offset')
 const scrollTo = require('./dom/scrollTo')
 const setScrollTop = require('./dom/setScrollTop')
 const windowResize = require('./dom/windowResize')
+const imgLazy = require('./dom/imgLazy')
 
 const debounce = require('./function/debounce')
 const throttle = require('./function/throttle')
@@ -30,6 +31,7 @@ const isEmptyObject = require('./object/isEmptyObject')
 
 const randomColor = require('./random/randomColor')
 const randomNum = require('./random/randomNum')
+const randomID = require('./random/randomID')
 
 const isEmail = require('./regexp/isEmail')
 const isIdCard = require('./regexp/isIdCard')
@@ -66,6 +68,7 @@ module.exports = {
     scrollTo,
     setScrollTop,
     windowResize,
+    imgLazy,
 
     debounce,
     throttle,
@@ -77,6 +80,7 @@ module.exports = {
 
     randomColor,
     randomNum,
+    randomID,
 
     isEmail,
     isIdCard,
diff --git a/src/random/randomID.js b/src/random/randomID.js
new file mode 100644
index 0000000..2e556d9
--- /dev/null
+++ b/src/random/randomID.js
@@ -0,0 +1,13 @@
+/**
+ * 生成随机ID
+ * @param {Number} randomLength 长度
+ * @return {String} 
+ */
+function randomID(randomLength = 8) {
+  return Number(
+    Math.random()
+      .toString()
+      .substr(3, randomLength) + Date.now()
+  ).toString(36);
+}
+module.exports = randomID;
\ No newline at end of file