Article 6: How to validate duplicate key and require value using javascript and SPServices

Step 1: Download 2 file javascript at here

jquery-1.4.2.js //Use Jquery library

jquery.SPServices-0.5.6.js//Use Webservices

Step 2: Go to Top level site | On home page | Click to Shared Documents | Upload 2 file jquery-1.4.2.js and jquery.SPServices-0.5.6.js

Step 3: Create new list name Employees

Change Title to EmployeeID //Similar Primary key but don’t set Unique

Create Fields as follows: FirstName (Single line of text), LastName (Single line of text), FullName (Calculated (calculation based on FirstName and LastName columns))

Step 4: Go to NewForm.aspx

Step 5: Add Content Editor Webpart

Step 6: Open HTML Source

Step 7: Copy code and paste to here

<script src="../../Shared Documents/jquery-1.4.2.js" type="text/javascript"></script>

    <script src="../../Shared Documents/jquery.SPServices-0.5.6.js" type="text/javascript"></script>

    <script>   

var isSave=true;       

//use Chrome to get ID of Title Control from client

        vartxtTitle="#ctl00_m_g_091a1007_03bb_42bf_8842_9a04d3694c48_ctl00_ctl05_ctl00_ctl00_ctl00_ctl04_ctl00_ctl00_TextField";

        //Event Default of sharepoint "PreSaveAction"

        function PreSaveAction() {

        if ($(txtTitle).attr("value") != "") {

            isSave = true;

            $().SPServices({

                operation: "GetListItems",//Default

                async: false,//Default

                listName: "Employees",//Your List

                completefunc: function (xData, Status) {//Default

                    //Loop via all item

                    $(xData.responseXML).find("z\\:row").each(function () {

                        //Get value from List and compare with input value

                        if ($(txtTitle).attr("value") == $(this).attr("ows_Title")) {

                            isSave = false;

                        }

                    });

                }

            });

            //If valid

            if (isSave == true) {

                return true;

            }

            else {

                alert("Duplicate ...! Please Enter ... again");

                return false;

            }

        }

        else {

            alert("Please Enter ...");

            return false;

        }

    }

</script>

Step 8: Change something for appropriate with your structure

-          Change ID of Title Field by: Open chrome and Open NewForm.aspx page

-          Right click to TextBox EmployeeID then click Inspect element

-          Copy Id and replace your txtTitle

-          ctl00_m_g_091a1007_03bb_42bf_8842_9a04d3694c48_ctl00_ctl05_ctl00_ctl00_ctl00_ctl04_ctl00_ctl00_TextField

Step 9: Add new item which it is duplicate with item in list and see messagebox as follows

Try Input data again with different EmployeeID

Result as follow: