A frequent request: have the ID displayed when viewing an individual item, in display form (DispForm.aspx) and edit form (EditForm.aspx). This is for example useful when a team uses the default SharePoint ID as identifier in an Issue Tracking list.

Note: the ID cannot be displayed in NewForm.aspx, simply because the ID doesn’t exist yet when you add a new item.

The answer is easy: the ID is actually already in the browser window, in the URL to be precise:
http://…/Issue%20Tracking/DispForm.aspx?ID=1&Source=…

Right, this is not very user friendly, so we are going to add a short script to grab the ID and display it in the page.

To add a script to DispForm.aspx and EditForm.aspx, we’ll use a well known technique:
- append ?ToolPaneView=2 to the URL to switch to edit mode:
http://…/Issue%20Tracking/DispForm.aspx?ToolPaneView=2
- add a hidden CEWP to the page

Then add one of the two scripts below in the source editor of the CEWP:

To display the ID in the first row:

<script type="text/javascript">
//
// Item ID in DispForm.aspx and EditForm.aspx
// Feedback and questions: Christophe@PathToSharePoint.com
//
function DisplayItemID()
{
var regex = new RegExp("[\\?&]"+"ID"+"=([^&#]*)");
var qs = regex.exec(window.location.href);
var TD1 = document.createElement("TD");
TD1.className = "ms-formlabel";
TD1.innerHTML = "<h3 class='ms-standardheader'>Issue ID</h3>";
var TD2 = document.createElement("TD");
TD2.className = "ms-formbody";
TD2.innerHTML = qs[1];
var IdRow = document.createElement("TR");
IdRow.appendChild(TD1);
IdRow.appendChild(TD2);
var ItemBody = GetSelectedElement(document.getElementById("idAttachmentsRow"),"TABLE").getElementsByTagName("TBODY")[0];
ItemBody.insertBefore(IdRow,ItemBody.firstChild);
}

_spBodyOnLoadFunctionNames.push("DisplayItemID");
</script>

To display the ID in the last row:

<script type="text/javascript">
//
// Item ID in DispForm.aspx and EditForm.aspx
// Feedback and questions: Christophe@PathToSharePoint.com
//
function DisplayItemID()
{
var regex = new RegExp("[\\?&]"+"ID"+"=([^&#]*)");
var qs = regex.exec(window.location.href);
var TD1 = document.createElement("TD");
TD1.className = "ms-formlabel";
TD1.innerHTML = "<h3 class='ms-standardheader'>Issue ID</h3>";
var TD2 = document.createElement("TD");
TD2.className = "ms-formbody";
TD2.innerHTML = qs[1];
var IdRow = document.createElement("TR");
IdRow.appendChild(TD1);
IdRow.appendChild(TD2);
var ItemBody = GetSelectedElement(document.getElementById("idAttachmentsRow"),"TABLE").getElementsByTagName("TBODY")[0];
ItemBody.appendChild(IdRow);
}

_spBodyOnLoadFunctionNames.push("DisplayItemID");
</script>