How to update a table row with save button using .ajax - asp.net

Question

I have a table which has one row and only one cell will be editable. I have accomplished this with the following code.
$("td#effEndDate").click(function() {
if (!$(this).hasClass("edit")) {
var value = jQuery.trim($(this).html());
$(this).html("<input id=\"txtEdit\" type=\"text\" value=\"" + value + "\" />");
$(this).addClass("edit");
$("#txtEdit").focus();
}
});
Now this is the part where i'm stuck.
After the field is updated a save button must be clicked to call the proper .ajax method to update the database. But how can I compare the previous value to the current value on a button press? Since i'm not using the onblur property where I could have saved the old value and passed it to the update function.

Answer 1

There are two possibilities.
Pass the variable around in between functions
Make the variable global
if you want the variable global do not use the "var" keyword
Change:
var value = jQuery.trim($(this).html());
To this:
value = jQuery.trim($(this).html());
Edit
If the click function is getting hit more then once before a page refresh and assuming you want to keep a copy of the original table rows you can try this. Save a copy of the original table in a variable then you can query the original table for the html using the ID number. Here is a quick mock
first store the table in a variable upon the page loading. This will save an original copy of the table
//get a copy of the table
var GetCopyofOriginalTable = function() {
var TableToBeCopied = $('the appropriate selector');
CopyOfTable = JQuery.extend(true, {}, TableToBeCopied); //Notice no var, its global
}
//Now store the variale
GetCopyofOriginalTable();
var FindTableRowByID = function(trID) {
return $('table:has(tr#' + trID));
}
Now you can loop through the new table test its value agaisnt the old table. This methed make use alot of memory depending on how big the table is.

Answer 2

I would store the original value somewhere in a variable, and compare the two in the submission function before sending the .ajax call.