diff --git a/README.md b/README.md
index 900c4482..86317353 100644
--- a/README.md
+++ b/README.md
@@ -685,6 +685,63 @@ This method returns you the nodes related to the specified node.
   </tr>
 </table>
 
+#### getParent($node)
+This method returns you the parent node of the specified node.
+<table>
+  <tr>
+    <th>Name</th>
+    <th>Type</th>
+    <th>Required</th>
+    <th>Default</th>
+    <th>Description</th>
+  </tr>
+  <tr>
+    <td>$node</td>
+    <td>JQuery Object</td>
+    <td>Yes</td>
+    <td></td>
+    <td>It's the desired JQuery Object to know its parent node</td>
+  </tr>
+</table>
+
+#### getSiblings($node)
+This method returns you the sibling nodes of the specified node.
+<table>
+  <tr>
+    <th>Name</th>
+    <th>Type</th>
+    <th>Required</th>
+    <th>Default</th>
+    <th>Description</th>
+  </tr>
+  <tr>
+    <td>$node</td>
+    <td>JQuery Object</td>
+    <td>Yes</td>
+    <td></td>
+    <td>It's the desired JQuery Object to know its sibling nodes</td>
+  </tr>
+</table>
+
+#### getChildren($node)
+This method returns you the child nodes of the specified node.
+<table>
+  <tr>
+    <th>Name</th>
+    <th>Type</th>
+    <th>Required</th>
+    <th>Default</th>
+    <th>Description</th>
+  </tr>
+  <tr>
+    <td>$node</td>
+    <td>JQuery Object</td>
+    <td>Yes</td>
+    <td></td>
+    <td>It's the desired JQuery Object to know its child nodes</td>
+  </tr>
+</table>
+
 #### setChartScale($chart, newScale)
 This method helps you set the specified chart with new scale.
 <table>
diff --git a/package-lock.json b/package-lock.json
index 88597375..eb3efa8c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "orgchart",
-  "version": "3.1.1",
+  "version": "3.1.2",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -5995,7 +5995,6 @@
           "version": "2.3.5",
           "resolved": "https://registry.npmjs.org/minipass/-/minipass-2.3.5.tgz",
           "integrity": "sha512-Gi1W4k059gyRbyVUZQ4mEqLm0YIUiGYfvxhF6SIlk3ui1WVxMTGfGdQ2SInh3PDrRTVvPKgULkpJtT4RH10+VA==",
-          "optional": true,
           "requires": {
             "safe-buffer": "^5.1.2",
             "yallist": "^3.0.0"
@@ -6213,8 +6212,7 @@
         "safe-buffer": {
           "version": "5.1.2",
           "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.1.2.tgz",
-          "integrity": "sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g==",
-          "optional": true
+          "integrity": "sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g=="
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -6317,8 +6315,7 @@
         "yallist": {
           "version": "3.0.3",
           "resolved": "https://registry.npmjs.org/yallist/-/yallist-3.0.3.tgz",
-          "integrity": "sha512-S+Zk8DEWE6oKpV+vI3qWkaK+jSbIK86pCwe2IF/xwIpQ8jEuxpw9NyaGjmp9+BoJv5FV2piqCDcoCtStppiq2A==",
-          "optional": true
+          "integrity": "sha512-S+Zk8DEWE6oKpV+vI3qWkaK+jSbIK86pCwe2IF/xwIpQ8jEuxpw9NyaGjmp9+BoJv5FV2piqCDcoCtStppiq2A=="
         }
       }
     },
diff --git a/package.json b/package.json
index 52ffafa0..8968e111 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "orgchart",
-  "version": "3.1.1",
+  "version": "3.1.2",
   "description": "Simple and direct organization chart(tree-like hierarchy) plugin based on pure DOM and jQuery.",
   "main": "./dist/js/jquery.orgchart.min.js",
   "style": [
@@ -8,6 +8,7 @@
   ],
   "scripts": {
     "test": "gulp test",
+    "unit-tests": "gulp unit-tests",
     "build": "gulp build",
     "start": "gulp serve"
   },
diff --git a/test/unit/tests.js b/test/unit/tests.js
index 9bfd69f0..a191ae34 100644
--- a/test/unit/tests.js
+++ b/test/unit/tests.js
@@ -184,7 +184,8 @@ describe('orgchart -- unit tests', function () {
 
   it('getRelatedNodes()', function () {
     oc.getRelatedNodes().should.deep.equal($());
-    oc.getRelatedNodes($('td:first'), 'children').should.deep.equal($());
+    oc.getRelatedNodes({}, 'children').should.deep.equal($());
+    oc.getRelatedNodes($('.hierarchy:first'), 'children').should.deep.equal($());
     oc.getRelatedNodes($('.node:first'), 'child').should.deep.equal($());
 
     oc.getRelatedNodes($laolao, 'parent').should.deep.equal($());
@@ -196,6 +197,37 @@ describe('orgchart -- unit tests', function () {
     oc.getRelatedNodes($bomiao, 'siblings').toArray().should.members([$sumiao[0], $hongmiao[0]]);
   });
 
+  it('getParent()', function () {
+    oc.getParent().should.deep.equal($());
+    oc.getParent({}).should.deep.equal($());
+    oc.getParent($('.hierarchy:first')).should.deep.equal($());
+
+    oc.getParent($laolao).should.deep.equal($());
+    oc.getParent($bomiao).should.deep.equal($laolao);
+    oc.getParent($sandan).should.deep.equal($pangpang);
+  });
+
+  it('getSiblings()', function () {
+    oc.getSiblings().should.deep.equal($());
+    oc.getSiblings({}).should.deep.equal($());
+    oc.getSiblings($('.hierarchy:first')).should.deep.equal($());
+
+    oc.getSiblings($laolao).should.deep.equal($());
+    oc.getSiblings($bomiao).toArray().should.members([$sumiao[0], $hongmiao[0]]);
+    oc.getSiblings($sandan).should.deep.equal($());
+  });
+
+  it('getChildren()', function () {
+    oc.getChildren().should.deep.equal($());
+    oc.getChildren({}).should.deep.equal($());
+    oc.getChildren($('.hierarchy:first')).should.deep.equal($());
+
+    oc.getChildren($laolao).toArray().should.members([$bomiao[0], $sumiao[0], $hongmiao[0]]);
+    oc.getChildren($bomiao).should.deep.equal($());
+    oc.getChildren($sumiao).toArray().should.members([$tiehua[0], $heihei[0], $pangpang[0]]);
+    oc.getChildren($sandan).should.deep.equal($());
+  });
+
   it('hideParent()', function () {
     var spy  = sinon.spy(oc, 'hideParent');
     var spy2  = sinon.spy(oc, 'hideSiblings');