Assumptions:
The value to be set is passed in the query string url. Example:

<SiteURL>/sites/newform.aspx?ID=3&RollNo=10
The list has a drop down field say “ID”.
The list has a single line text field say “Roll No”.

Steps:

  1. Open the newform.aspx page of a list.
  2. Edit the page.
  3. Add a new script editor webpart.
  4. Add the below code to the script editor webpart.
  1. <script src="/sites/test/SiteAssets/jquery-1.10.2.js"></script>
  2. < script src="/sites/test/SiteAssets/sputility.min.js"></script>
  3. <script language="javascript" type="text/javascript">
  4. $(document).ready(function()
  5. {
  6. var ID = GetUrlKeyValue('ID');
  7. var rollNo = GetUrlKeyValue('RollNo');
  8. $("Select[Title='ID']").val(ID);
  9. $("Select[Title='ID']").prop("disabled", "disabled");
  11. $("input[Title='Roll No']").val(rollNo);
  12. $("input[Title='Roll No']").prop("disabled", "disabled");
  14. });
  15. </script>
Explanation:
  1. Reference needs to be made to jquery and SPUtility.js files.
  2. GetURLKeyValue(‘<parameter>’) – gets the value from the query string.
  3. $("Select[Title='ID']").val(ID); à "select" is used for drop down fields, its setting the value as per the query string value.
  4. $("input[Title='Roll No']").val(rollNo); à”input” is used for text fields and is setting the value as per the query string parameter.
  5. $("Select[Title='ID']").prop("disabled", "disabled"); à After setting the value this line, is setting the fields as disabled.