Attach Custom Button on Editform.aspx and Newform

Including the "Custom " Button to the Page
Open the SharePoint Site containing the List to modify using SharePoint Designer
2007 and use the Folder List to navigate to the target List under the folder Lists
(In this example, I will be using the Links list that comes along with any site
created using the Team Site site template). Double click on the NewForm.aspx page.
The NewForm.aspx page would open in code view. Identify the Content control with the
ContentPlaceHolderId of PlaceHolderMain. We will be actively inserting extra
JavaScript and HTML within this Content control that will alter the behavior of the
page. First of all, let's insert the appearance of the 2 HTML elements that we will
be inserting into the rendered page. The <table> element here is made hidden
as it serves no purpose but as a "host" to the 2 <td> elements that
are marked with their respective IDs which we will be using later. Note that the
first <td> element contains the "OK and New" button that will
perform certain custom JavaScript function when clicked upon. We will be diving into
the JavaScript function's details later. Insert the HTML code right above the
closing tag of the Content control </asp:Content>.

<table style="display:none">
<tr>
<td id="oCustomButton" class="ms-toolbar" nowrap="true">
<table cellpadding="0" cellspacing="0" width="100%">
<tr>
<td align="right" width="100%" nowrap>
<input type="button" value="Custom Button"
onclick="submitForm()" class="ms-ButtonHeightWidth" target="_self" />
</td>
</tr>
</table>
</td>
<td id="oSeparator" class="ms-separator"> </td>
</tr>
</table>

Next task is inserting the relevant elements into the right position on the page,
such that it appears next to the OK button, along the Cancel button as well.
Insert the following JavaScript code into a script element into the page right below
the above pasted HTML codes:

<script language="javascript" type="text/javascript">
function attachCustomButton()
{ var oAryTables = new Array();
var oCustomButton = null;
var oSeparator = null;
var oNodeTemp = null;
oCustomButton = document.getElementById("oCustomButton");
oSeparator = document.getElementById("oSeparator");
oAryTables = document.getElementsByTagName("table");
for(var i = 0; i < oAryTables.length; i++)
{ if(oAryTables[i].className == "ms-formtoolbar")
{ oNodeTemp =
oAryTables[i].firstChild.firstChild.insertBefore(oSeparator.cloneNode(true),
oAryTables[i].firstChild.firstChild.firstChild.nextSibling);
oAryTables[i].firstChild.firstChild.insertBefore(oCustomButton.cloneNode(true),
oNodeTemp);
}
}
} _spBodyOnLoadFunctionNames.push("attachCustomButton");
</script>

Now write your own code for the ButtonClick Event.
;)

Add New Event to Buttons of default Newform.aspx, Dispform.aspx and Editform.aspx

There comes a situation when you want the default Ok or Edit item or close buttons 
in SharePoint forms pages like Newform.aspx, Dispform.aspx and Editform.aspx to
 redirect user to new page then specified.

To do that we can use java script code to redirect users to different page then the
 normal ones.
I am using an instant of giving an alert to user when user clicks on Ok button of 
editform.aspx .

I am using content editor webpart to add javascript code to editform.aspx page.
You can look into by earlier post if you are not aware of method to put content 
editor webpart in editform.aspx page.

Here is the post click here
After the Webpart is added, make sure the Inside Layout Tab, the Hidden checkmark is
 checked, to hide the webpart during normal use.

In the content editor webpart , put this javascript code:
Replace [] with < >



[script language="javascript" type="text/javascript"]

_spBodyOnLoadFunctionNames.push("StartUpCustomScript");
function StartUpCustomScript() {  
  ChangeOkButtonOnclickEvent("Input","SaveItem");
}
function ChangeOkButtonOnclickEvent(tagName, identifier) {
  var len = identifier.length;
  var tags = document.getElementsByTagName(tagName); 
 /*find all Input type controls on page (ie. control with tag [Input/])*/
  for (var i=0; i < tags.length; i++) {
        var tempString = tags[i].name;       
        if(tempString.indexOf(identifier) == tempString.length-len ) /*find any 
Input type controls on page has its name ending with 'SaveItem'*/
        {
           /*if found, replace it default onclick with our custom script*/

           var func = tags[i].attributes["onclick"].value.replace("if 
(!PreSaveItem())","alert('you have clicked OK');if (!PreSaveItem())");
           /*remove its default onclick event*/
           tags[i].onclick = null;
           /*re-register its onlick event with new script*/
           tags[i].attachEvent("onclick",new Function(func));
       }
    }
    return null;
}  
[/script]




Adding this now as soon as from editform.aspx when you click Ok button , a alert 
message will pop up.



Job done :)