Develop Reference

Show hide/div based on drop down value at page load

I have the following code that I use to hide/show a div using a drop-down. If the Value of the drop-down is 1, I show the div, otherwise I hide it.
var pattern = jQuery('#pattern');
var select = pattern.value;
pattern.change(function () {
if ($(this).val() == '1') {
$('#hours').show();
}
else $('hours').hide();
});
The select drop down retrieves its value from the database using form model binding:
<div class="form-group">
<label for="pattern" class="col-sm-5 control-label">Pattern <span class="required">*</span></label>
<div class="col-sm-6">
{{Form::select('pattern',['0'=> 'Pattern 0','1'=> 'Pattern 1'],null,
['id'=>'pattern','class' => 'select-block-level chzn-select'])}}
</div>
</div>
This select drop-down then hides or shows the following div:
<div id="hours" style="border-radius:15px;border: dotted;" >
<p>Example text</p>
</div>
The problem:
The div won't be hidden if the pattern stored in the database is set to 0. I have to manually select "Pattern 0" from the drop down to change it. I know that is due to the .change() method. But how do I make it hide/show on page load?

Usually in such case I store the anonymous function reference as below:
var checkPattern = function () {
if ($('#pattern').val() == '1') {
$('#hours').show();
}
else $('#hours').hide();
}
It makes the code ready to use in more then one place.
Now your issue could be resolve in a more elegant way:
$(document).ready(function(){
// add event handler
$('#pattern').on('change', checkPattern);
// call to adjust div
checkPattern();
});

Well, if the element "should" be visible by default, you just then have to check condition to "hide it" (you don't have to SHOW an element that is already visible...) :
if(pattern.value != %WHATEVER%) { $('#hours').toggle(); }
Then, to switch display on event or condition or whatever :
pattern.change(function(evt){
$('#hours').toggle();
});
Not sure that your event will work. I'd try something like
$(document).on(..., function(evt){
//behaviour
});
http://api.jquery.com/toggle/
https://learn.jquery.com/events/handling-events/

Check input elements responsively when changed

I have this code. It obviously calls function when selected element is focused. The function then checks if selected element has length less than 3, and if it does it changes background color of the element.
$('#register-form input[type="text"]').focus(function(){
if ($(this).length < 3) {
$(this).css('background','#f00');
}
});
Now the problem is that when there are more than 4 characters within input, color still remains. The problem is that it calls function when element is focused. After that, it doesn't check the if statement anymore, as obviosuly function is never called again.
The solution I seek; I want it to check if the IF statement is still legit once the input element value is changed. Or any other smooth way to check IF statements and calls functions in a live time.
The answer to this question is simple and well known. However, as you answer please provide some information related to this question; What are the best ways to check various changes in statements lively? What are the best ways to make website 'alive' and respond to any actions immediately?

Give the error a class and use onkeyup (and change if you wish - which triggers on blur too)
Also test the .val().length instead:
<style>
.error { background-color:red }
</style>
$('#register-form input[type="text"]').on("keyup,change",function(){
$(this).toggleClass("error", $(this).val().length < 3);
}).keyup(); // trigger on load
$(function() {
$('#register_form input[type="text"]').on("keyup", function() {
$(this).toggleClass("error", $(this).val().length < 3);
console.log("error")
}).keyup(); // initialise in case of reload
});
.error {
color: red
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<form id="register_form">
<input type="text" />
<input type="text" />
<input type="text" />
</form>

Try this:
$('#register-form input[type="text"]').on("focus input", function(){
$(this).css('background', $(this).val().length < 3 ? '#f00' : '#fff');
});
EDIT
Personally, I use AngularJS alot for web applications that have alot of these. E.g. you can do this:
<input type="text" ng-model="myValue" ng-style="{'background-color', myValue.length < 3 ? '#f00' : '#fff'}"/>

Disabling a textbox when the other textbox have a value HTML

im sorry for this question but how can i disable a textbox if another textbox have a value??
I already try this code but its not working,, sorry for the noob question T_T
function disable(downpayment,full_payment)
{
if ( downpayment.value.length >= 1 )
document.getElementById(full_payment).disabled = true;
else
document.getElementById(full_payment).disabled = false;
}
</script>
<input name="downpayment" id="downpayment" type="text" onselect="function disable(downpayment,full_payment);" style="width:250px" />
</p>
<p>
<input name="full_payment" id="full_payment" type="text" style="width:250px" />

If you want to stay with plain JavaScript:
// finding the relevant elements *outside* the function
var downpayment = document.getElementById('downpayment'),
full_payment = document.getElementById('full_payment');
function enableToggle(current, other) {
/* 'current' is the element that currently has focus
'other' is the other input element, that does not have focus.
1. if the 'current' value of the focused/active element, once the whitespace
is removed, is greater than 0 (so it has something in it other than whitespace,
the disabled property of the 'other' element is true,
2. if the 'current' element has only whitespace, and/or a zero-length value,
the 'other' element's disabled property is false.
*/
other.disabled = current.value.replace(/\s+/,'').length > 0;
}
// using the onkeyup event to call a function on the elements.
downpayment.onkeyup = function () {
enableToggle(this, full_payment);
}
full_payment.onkeyup = function () {
enableToggle(this, downpayment);
}
This works with the following HTML:
<input name="downpayment" id="downpayment" type="text" style="width:250px" />
<input name="full_payment" id="full_payment" type="text" style="width:250px" />
JS Fiddle demo.
If you're using jQuery already, then you can either nest the above into jQuery's $(document).ready(function(){ /* the code in here */});, or switch to a jQuery-only solution, such as Alex's.
To stick with plain-JavaScript, and avoiding explaining how to set up an equivalent DOM-ready event, put the following at the end of your HTML content, just before the closing </body> tag:
<script>
var downpayment = document.getElementById('downpayment'),
full_payment = document.getElementById('full_payment');
function enableToggle(current, other) {
other.disabled = current.value.replace(/\s+/,'').length > 0;
}
downpayment.onkeyup = function () {
enableToggle(this, full_payment);
}
full_payment.onkeyup = function () {
enableToggle(this, downpayment);
}
</script>
(This is exactly the same JavaScript as above, with the comments stripped out, but wrapped in <script></script> tags)
Putting this at the bottom of the HTML means that the elements exist in the DOM prior to your trying to assign event-handlers to them.
Incidentally, with adjusted HTML, to give:
<form>
<!--
I associated the relevant elements with a class-name 'enableToggle',
you don't have to, it just reduces the work the jQuery has to do later
when using siblings('.enableToggle') to find the relevant elements.
-->
<div>
<label for="downpayment">Downpayment</label>
<input name="downpayment" class="enableToggle" id="downpayment" type="text" style="width:250px" />
<label for="full_payment">Full payment</label>
<input name="full_payment" class="enableToggle" id="full_payment" type="text" style="width:250px" />
</div>
</form>
The following jQuery could be used:
// binds both event-handler to both 'keyup' and 'paste' events.
$('.enableToggle').on('keyup paste', function(){
/* 'curVal' is a Boolean (true or false) depending on whether there's
a value other than whitespace */
var curVal = $(this).val().replace(/\s+/g,'').length > 0;
/* sets the 'disabled' property of the sibling elements of the current
element, as long as those siblings have the class 'enableToggle'
(this avoids having to explicitly identify all the elements you want
to act on). */
$(this).siblings('.enableToggle').prop('disabled', curVal);
});
JS Fiddle demo.

You have tagged the question jQuery, so it's as simple as...
$("#downpayment").on("change paste", function() {
$("#full_payment").prop("disabled", this.value.length);
});
As soon as your down payment has some content in it (even if it's a space, if that's not ideal, $.trim() the input before you check its length property) then it will enable the full payment.

$(document).ready(function()
{
$(".PaxHeads").on('keypress','input[name="DebitAmount"]',function()
{
var myLength = $('input[name="DebitAmount"]').val().length;
if (myLength!=0)
{
$('input[name="CreditAmount"]').attr("disabled", "disabled");
}
else
{
$('input[name="CreditAmount"]').removeAttr("disabled");
}
});
$(".PaxHeads").on('keypress', 'input[name="CreditAmount"]', function()
{
var myLength1 = $('input[name="CreditAmount"]').val().length;
if (meLength1!=0)
{
$('input[name="DebitAmount"]').attr("disabled", "disabled");
}
else
{
$('input[name="DebitAmount"]').removeAttr("disabled");
}
});
});

using jquery to change contents of form upon typing

I am trying to get the default value to not go away on click, but rather when the user starts typing (so they know what the field is for)....the problem is the following:
when I use onchange instead of onfocus it keeps the default value in there when they start typing. If its confusing what I am doing go to facebook and look how their search box works...thats what I am going for.
<script>
function uFocus() {
$('#fakeusername').hide();
$('#username').show();
$('#username').focus();
}
function uBlur() {
if ($('#username').attr('value') == '') {
$('#username').hide();
$('#fakeusername').show();
}
}
</script>
<input style='width:202px;height:25px;margin-top:8px;font-size:14px;color:gray;' type='text' name='fakeusername' id='fakeusername' value=' Username' onfocus='uFocus()' />
<input style='width:202px;height:25px;margin-top:8px;font-size:14px;color:#000000;display: none' type='text' name='username' id='username' value='' onblur='uBlur()' />

Two options:
In HTML5, the placeholder attribute will simulate what you want with no Javascript needed.
<input type='text' name='fakeusername' id='fakeusername' value='Username' placeholder='Type your username' />
The second, and I believe the approach used by Facebook, is to swap a background image containing the sample text with a blank one. So you might create two background images (the first containing the words "Type your username" in the font used by the input, the second a blank) and set them to flip whenever the input is focused.

Is this what you are looking for:
$("#fakeusername").on({
focus: function() {
$(this).css('color', '#000');
},
blur: function() {
$(this).css('color', 'grey');
},
keydown: function() {
if ($(this).val()==' Username') {
$(this).val('');
}
}
});
FIDDLE

Here's a method that places label over top of input and requires proper for/ID match to allow browser to do default focus of input when clicking on label. Positions label over top of input, if no value of input on blur will show label again. Using label makes it accessible
http://jsfiddle.net/UCxaZ/2

Default text on input

How to set blank default text on input field and clear it when element is active.

In modern browsers, you may set the placeholder attribute on a field to set its default text.
<input type="text" placeholder="Type some text" id="myField" />
However, in older browsers, you may use JavaScript to capture the focus and blur events:
var addEvent = function(elem, type, fn) { // Simple utility for cross-browser event handling
if (elem.addEventListener) elem.addEventListener(type, fn, false);
else if (elem.attachEvent) elem.attachEvent('on' + type, fn);
},
textField = document.getElementById('myField'),
placeholder = 'Type some text'; // The placeholder text
addEvent(textField, 'focus', function() {
if (this.value === placeholder) this.value = '';
});
addEvent(textField, 'blur', function() {
if (this.value === '') this.value = placeholder;
});
Demo: http://jsbin.com/utecu

Using the onFocus and onBlur events allows you to achieve this, I.e.:
onfocus="if(this.value=='EGTEXT')this.value=''"
and
onblur="if(this.value=='')this.value='EGTEXT'"
The full example is as follows:
<input name="example" type="text" id="example" size="50" value="EGTEXT" onfocus="if(this.value=='EGTEXT')this.value=''" onblur="if(this.value=='')this.value='EGTEXT'" />

Or simply
<input name="example" type="text" id="example" value="Something" onfocus="value=''" />
This will not post back the default text once the box is cleared but also will allow the user to clear the box and see all results in the case of an autocomplete script.

Declare styles for inactive and active states:
.active {
color: black;
}
.inactive {
color: #909090;
}
Add the Javascript to handle the changing of state:
function toggleText(el)
{
var v = el.value;
//Remove text to allow editing
if(v=="Default text") {
el.value = "";
el.className = "active";
}
else {
//Remove whitespace
if(v.indexOf(" ")!=-1) {
split = v.split(" ").join("");
v = split;
}
//Change to inactive state
if(v=="") {
el.value = "Default text";
el.className = "inactive";
}
}
}
Add your input box, with the default value set, the inactive class set and Javascript handlers pointing to the toggleText() function (you could use event listeners to do this if you wish)
<input type="text" value="Default text" class="inactive" onFocus="toggleText(this);" onBlur="toggleText(this);">

From a usability point of view the text in the input component should be preserved only for user's input purposes. The possible default value in the input should be valid if left untouched by the user.
If the placeholder text is meant to be a hint for how to fill the input, it is better to be blaced near the input where it can be seen also when the input has been filled. Moreover, using a placeholder text inside text components can cause troubles e.g. with braille devices.
If a placeholder text is used, regardless of usability guidelines, one should make sure that it is done in an unobtrusive way so that it works with user agents without javascript or when js is turned off.

I have found jQuery plugin (http://www.jason-palmer.com/2008/08/jquery-plugin-form-field-default-value/) and use it :)

What I did is put a placeholder attribute for modern browsers:
<input id='search' placeholder='Search' />
Then, I made a fallback for older browsers using JQuery:
var placeholder = $('search').attr('placeholder');
//Set the value
$('search').val(placeholder);
//On focus (when user clicks into the input)
$('search').focus(function() {
if ($(this).val() == placeholder)
$(this).val('');
});
//If they focus out of the box (tab or click out)
$('search').blur(function() {
if ($(this).val() == '')
$(this).val(placeholder);
});
This works for me.

You can use this plugin (I'm an co-author)
https://github.com/tanin47/jquery.default_text
It clones an input field and put it there.
It works on IE, Firefox, Chrome and even iPhone Safari, which has the famous focus problem.
This way you do not have to be worried about clearing input field before submitting.
OR
If you want to HTML5 only, you can just use attribute "placeholder" on input field

You can use placeholder attribute.
np. <input type="text" name="fname" placeholder="First name">
check http://www.w3schools.com/tags/att_input_placeholder.asp