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How to hide the select value from the form

I have a form which have a select drop down. i have disabled it by default and will re enable it based on some conditions. i don't want anybody to access the select option values when it is disabled(now it can be viewed by inspecting the element from browser). how do i make it secure?

I don't think you can. You might be better off populating it when it's needed instead of enabling it. You could do that with an Ajax call.

You need to use ngIf directive.
The ngIf directive removes or recreates a portion of the DOM tree based on an {expression}. If the expression assigned to ngIf evaluates to a false value then the element is removed from the DOM, otherwise a clone of the element is reinserted into the DOM.
Usage
<select ng-if="someCondition"></select>

If you use a simple binding library like knockout.js you can use container-less binding which will only render the select DOM when you want.
Knockout is is a great little library which plays nicely with most other libraries so shouldn't cause any trouble, all you ned to do is import the js file.
Container-less binding will only render the DOM when it needs to, so inspecting the page element will not display the select box.
<!--ko if: IsShown -->
<select>Render Me</select>
<!--/ko-->
Here is a simple fiddle to show you how to make it work.
Knockout Containerless Binding

You could avoid rendering it, which would hide it from the DOM inspector, but the data would still be in the browser and available to a user who cared to look in the right place.
If you don't want the user to see the data, then don't send it to the client in the first place.
When you want to display the select element, make an Ajax request to the server. Then perform authentication and authorisation to make sure the user is allowed to see the data. Then return it in the response and have Angular generate the select using that data.

There is no way to hide part of code from viewing by user in browser, because browsers have to see the code to run it, so it can be viewed by user. But, using php can help you to generate content for page only when it's needed. I think you can generate content for your drop-down, or the whole dropdown using that way.

Calling a Javascript function on focus of a page based on user interaction

I have a requirement where clicking on an icon should open a new window where the user will be able to view and edit certain fields. After the user closes this window and comes back to parent window, the icon color and text should be changed( for eg:- if the user has removed certain data, the icon will change to red color and text is set to null. If the user presses cancel button, nothing changes)
I am planning to implement this using a body onload function which essentially checks with the database using AJAX requests to see if the user has changed the data, then accordingly change the icon and text.
But, I see 2 problems in this approach
1. There will be a AJAX call even if the user has not changed anything.(ie. pressed Cancel button)
2. AJAX is called every time the body is on focus. Eg:- He may be working on some other page (or a different browser altogether) and comes back to this, resulting in an AJAX call.
Can anybody suggest a better approach.
I am using Javacript, JSP, Java

Two ways to implement this
Method 1
You know the methods which changes the database in the opened form. Suppose you have a delete method, write an additional window.opener.location.reload() after the method. The downside is that opener(parent window) gets reloaded every time you change something in the child window. Which is unnecessary.
Method 2 - Using cookies
I am using MDN's A little framework: a complete cookies reader/writer with full unicode support for creating cookies. The plan of action will be this. Create a cookie and set a value for it like this after you change anything in the child window and update it in the database like this docCookies.setItem("isChildFormUpdated", "yes");. You can use the same cookie for every action you do. Now when you navigate back to the parent form, do this.
$(document).ready() {
$(window).focus(function () {
var formCookie = docCookies.getItem("isChildFormUpdated");
if (formCookie !== null && formCookie == "yes") {
//resetting the cookie. you can also remove the cookie
docCookies.setItem("isChildFormUpdated", "no");
//docCookies.removeItem("isChildFormUpdated");
// your ajax call comes here
//or you could simply reload the form so that we get fresh data
//window.location.reload(); // it will be heavier
}
});
});
I hope you get the basic idea.

I think the easiest way to do this would be to set a cookie (learn how here). You can then have the two windows communicate between each other. This wouldn't be AJAX, but it will most likely work.

Another nice way to create a popup-like box is by using a modal box. These can be complicated but they look very nice. You have to make a jQuery plugin in, but you can take the one here and learn how it works. Good luck with your requirement.

Use JavaScript to disable all buttons on a page until a refresh

I have a page that will cause an error if a user tries to click too many buttons at one time (for the impatient user) and therefore need to DISable any button (all defined by a JS onclick function) on the page until it is refreshed (with new data sent via the server using Java.) What is the best method to do this, and is there a way to do it with jQuery?

You would have to find all types of buttons using something like this..
$('input[type="submit"], button')
and loop through the returned array and do .attr('disabled','disabled'); on the item in each iteration.

How about simply calling this when you want to disable the buttons:
jQuery('input[type="button"]').attr('disabled', 'disabled');
That will disable all inputs of type button on the page. Of course, as soon as you reload/replace the page contents, the new buttons will not be disabled. You can also just disable all inputs if that's easier.
Fiddle: http://jsfiddle.net/duffmaster33/xDMux/

The single best solution is to use the BlockUI plugin for jQuery. It accomplished everything I needed and more. http://www.malsup.com/jquery/block/

Modal Windows using jQuery

I'm working on a web app where in I need to add some values inputted by the user.
When the user clicks on the Add button he sees a form and these values then show up on the page. Now to implement this I can do two things
Use a modal window
Make a form inside the page itself(in a div) and toggle its visibility by the Add button.
If I go with the former solution is it necessary to use Ajax or I can add elements on the main page directly itself? Are there any jQuery plugins to accomplish the same?

As Diodeus mentioned, you don't need Ajax.
In answer to your other question about the plugins, have a look at jQuery UI Dialog for the dialog. Generating the form is pretty trivial. There's no need for a plugin there

You don't need to use Ajax to accomplish this. The difference in the two methods is simply whether you use an inline block of code that is hidden and displayed later, or whether you use an absolutely-positioned block of code doing exactly the same thing.
In most cases there is a single form that envelops the entire page. The rest is a matter of a CSS and positioning.

Advice about using Tabindex and javascript/jquery to make "tabbing" easier

I'm making a large and complex application and I need to set tabindexes to help user navigate through the pages. This is a private application so I don't have restriction about (ab)using javascript (jquery).
I currently have these questions.
1) How do you force with javascript (jquery) the browser to move the cursor inside a specific textbox as soon as a page has loaded? I noticed that often browsers don't automatically put the cursor inside the first tabindexed input. I want a surefire way that forces it there no matter what.
2) Some fields that activate ui enanchement (namely jquery ui datepicker) have problems with tabbing (like having to push tab two time to go away from it), is there any way to avoid this?
3) How do you read and set tabindex with jquery? I have some fields that get hidden/shown based on user action and they should be able to "give" their tabindex to other fields if they get hidden, is this a problem, does the browser still consider a tabindex after the page has loaded?
Thank you very muchh

To put focus on a specific textbox, do this (assuming textbox id is #firstBox): $('#firstBox').focus(); See more examples here: How do you automatically set the focus...
Not particularly because the DatePicker is also its own UI, so it has various objects within it that can be focused on (which is what tabbing picks up on).
Actually, now that I've thought about it, if you hide a field (AKA, "hidden") it will not have a tabindex and the other tabs will fall in line with what is defined for the browser (typically top to bottom, left to right order). You shouldn't have to worry about setting the tabindex manually.