jQuery - set data() variable from $(this).val() - javascript

I have an e-mail form on my website, with four fields. Three text inputs and a text area. Each field has a default value attribute which serves as its label. I would like these values to be automatically unset/reset on their element's focus and focusout events.
I have the following JavaScript/jQuery code, which creates this behaviour.
$('input,textarea').data('default', "bleh");
$('input,textarea').focus(function() {
if($(this).val() === $(this).data('default')) {
$(this).val('');
}
});
$('input,textarea').focusout(function() {
if ($(this).val() === '')
{
$(this).val($(this).data('default'));
}
});
My problem comes in the storing of the initial data('default') attribute. I had tried using .data('default', $(this).val())... but apparently that is illegal and $(this) is not recognized.
I have tried to find a clean jQuery way to iterate over each of the elements, but I can't seem to find one.
Is there an easy way, using jQuery, to achieve what I want?

Unless I'm mistaken, there's no reason to be setting data properties on the element, you can make use of the elements defaultValue property:
$('input, textarea').focus(function() {
if (this.value === this.defaultValue) {
this.value = '';
}
});
$('input, textarea').focusout(function() {
if (!$.trim(this.value).length) {
this.value = this.defaultValue;
}
});
Here's a fiddle

There is no this, because you're not in a callback. You'll have to iterate over each matched element, setting their default one at a time.
The "clean jQuery way" is simply with each:
$('input,textarea').each(function () {
$(this).data('default', $(this).val());
});

You need iterate through the input elements and then set the value to data using .each()
$('input,textarea').each(function(){
var $this = $(this);
$this.data('default', $this.val())
});

Related

find select option with selected property using javascript

I have a view that loads select elements dynamically into the page on certain button clicks. Each of these selects have the same id value followed with an index value based on how many times the button is clicked. so the id would be like
id="my_id_" + numOfClicks;
I have also given all these selectors the same class value
class="selects"
What is the best way to have an event handler for when the selected option changes in any of the drop downs. right now I have the following:
$('.selects').change(function() {
if($('this option:selected').val() == 0) {
}
else {
}
});
So what I'm trying to do is first get the right select element using "this" then figure out which of the options are selected. Is there a better/more efficient way to do this?
As you say these get added at runtime, you'll want a delegated event handler. Within the handler, as the comments have pointed out, it's just $(this).val() to get the selected value of that select box. So:
$("selector for some container they're in").on("change", ".selects", function() {
if($(this).val() == 0) {
}
else {
}
});
For instance, if they're all inside an element with the class container, then:
$(".container").on("change", ".selects", function() {
if($(this).val() == 0) {
}
else {
}
});
If there's no other suitable container, you can just use $(document).on(..., but usually it's better to handle things a bit closer to where they are than that.
Side note: Values are always strings, but == will coerce, so "0" == 0 is true. Still, it's useful to remember that they're strings.
Assuming html input.selects:
$('body').on('change', '.selects', function() {
if($(this).val() == '0') {
}
else {
}
});
http://jsfiddle.net/r4pxx0yy/1/
No quote around this.

javascript/jquery: hide and uncheck, checked option/options [duplicate]

I'd like to do something like this to tick a checkbox using jQuery:
$(".myCheckBox").checked(true);
or
$(".myCheckBox").selected(true);
Does such a thing exist?
Modern jQuery
Use .prop():
$('.myCheckbox').prop('checked', true);
$('.myCheckbox').prop('checked', false);
DOM API
If you're working with just one element, you can always just access the underlying HTMLInputElement and modify its .checked property:
$('.myCheckbox')[0].checked = true;
$('.myCheckbox')[0].checked = false;
The benefit to using the .prop() and .attr() methods instead of this is that they will operate on all matched elements.
jQuery 1.5.x and below
The .prop() method is not available, so you need to use .attr().
$('.myCheckbox').attr('checked', true);
$('.myCheckbox').attr('checked', false);
Note that this is the approach used by jQuery's unit tests prior to version 1.6 and is preferable to using $('.myCheckbox').removeAttr('checked'); since the latter will, if the box was initially checked, change the behaviour of a call to .reset() on any form that contains it – a subtle but probably unwelcome behaviour change.
For more context, some incomplete discussion of the changes to the handling of the checked attribute/property in the transition from 1.5.x to 1.6 can be found in the version 1.6 release notes and the Attributes vs. Properties section of the .prop() documentation.
Use:
$(".myCheckbox").attr('checked', true); // Deprecated
$(".myCheckbox").prop('checked', true);
And if you want to check if a checkbox is checked or not:
$('.myCheckbox').is(':checked');
This is the correct way of checking and unchecking checkboxes with jQuery, as it is cross-platform standard, and will allow form reposts.
$('.myCheckBox').each(function(){ this.checked = true; });
$('.myCheckBox').each(function(){ this.checked = false; });
By doing this, you are using JavaScript standards for checking and unchecking checkboxes, so any browser that properly implements the "checked" property of the checkbox element will run this code flawlessly. This should be all major browsers, but I am unable to test previous to Internet Explorer 9.
The Problem (jQuery 1.6):
Once a user clicks on a checkbox, that checkbox stops responding to the "checked" attribute changes.
Here is an example of the checkbox attribute failing to do the job after someone has clicked the checkbox (this happens in Chrome).
Fiddle
The Solution:
By using JavaScript's "checked" property on the DOM elements, we are able to solve the problem directly, instead of trying to manipulate the DOM into doing what we want it to do.
Fiddle
This plugin will alter the checked property of any elements selected by jQuery, and successfully check and uncheck checkboxes under all circumstances. So, while this may seem like an over-bearing solution, it will make your site's user experience better, and help prevent user frustration.
(function( $ ) {
$.fn.checked = function(value) {
if(value === true || value === false) {
// Set the value of the checkbox
$(this).each(function(){ this.checked = value; });
}
else if(value === undefined || value === 'toggle') {
// Toggle the checkbox
$(this).each(function(){ this.checked = !this.checked; });
}
return this;
};
})( jQuery );
Alternatively, if you do not want to use a plugin, you can use the following code snippets:
// Check
$(':checkbox').prop('checked', true);
// Un-check
$(':checkbox').prop('checked', false);
// Toggle
$(':checkbox').prop('checked', function (i, value) {
return !value;
});
You can do
$('.myCheckbox').attr('checked',true) //Standards compliant
or
$("form #mycheckbox").attr('checked', true)
If you have custom code in the onclick event for the checkbox that you want to fire, use this one instead:
$("#mycheckbox").click();
You can uncheck by removing the attribute entirely:
$('.myCheckbox').removeAttr('checked')
You can check all checkboxes like this:
$(".myCheckbox").each(function(){
$("#mycheckbox").click()
});
You can also extend the $.fn object with new methods:
(function($) {
$.fn.extend({
check : function() {
return this.filter(":radio, :checkbox").attr("checked", true);
},
uncheck : function() {
return this.filter(":radio, :checkbox").removeAttr("checked");
}
});
}(jQuery));
Then you can just do:
$(":checkbox").check();
$(":checkbox").uncheck();
Or you may want to give them more unique names like mycheck() and myuncheck() in case you use some other library that uses those names.
$("#mycheckbox")[0].checked = true;
$("#mycheckbox").attr('checked', true);
$("#mycheckbox").click();
The last one will fire the click event for the checkbox, the others will not.
So if you have custom code in the onclick event for the checkbox that you want to fire, use the last one.
To check a checkbox you should use
$('.myCheckbox').attr('checked',true);
or
$('.myCheckbox').attr('checked','checked');
and to uncheck a check box you should always set it to false:
$('.myCheckbox').attr('checked',false);
If you do
$('.myCheckbox').removeAttr('checked')
it removes the attribute all together and therefore you will not be able to reset the form.
BAD DEMO jQuery 1.6. I think this is broken. For 1.6 I am going to make a new post on that.
NEW WORKING DEMO jQuery 1.5.2 works in Chrome.
Both demos use
$('#tc').click(function() {
if ( $('#myCheckbox').attr('checked')) {
$('#myCheckbox').attr('checked', false);
} else {
$('#myCheckbox').attr('checked', 'checked');
}
});
This selects elements that have the specified attribute with a value containing the given substring "ckbItem":
$('input[name *= ckbItem]').prop('checked', true);
It will select all elements that contain ckbItem in its name attribute.
Assuming that the question is...
How do I check a checkbox-set BY VALUE?
Remember that in a typical checkbox set, all input tags have the same name, they differ by the attribute value: there are no ID for each input of the set.
Xian's answer can be extended with a more specific selector, using the following line of code:
$("input.myclass[name='myname'][value='the_value']").prop("checked", true);
I'm missing the solution. I'll always use:
if ($('#myCheckBox:checked').val() !== undefined)
{
//Checked
}
else
{
//Not checked
}
To check a checkbox using jQuery 1.6 or higher just do this:
checkbox.prop('checked', true);
To uncheck, use:
checkbox.prop('checked', false);
Here' s what I like to use to toggle a checkbox using jQuery:
checkbox.prop('checked', !checkbox.prop('checked'));
If you're using jQuery 1.5 or lower:
checkbox.attr('checked', true);
To uncheck, use:
checkbox.attr('checked', false);
Here is a way to do it without jQuery
function addOrAttachListener(el, type, listener, useCapture) {
if (el.addEventListener) {
el.addEventListener(type, listener, useCapture);
} else if (el.attachEvent) {
el.attachEvent("on" + type, listener);
}
};
addOrAttachListener(window, "load", function() {
var cbElem = document.getElementById("cb");
var rcbElem = document.getElementById("rcb");
addOrAttachListener(cbElem, "click", function() {
rcbElem.checked = cbElem.checked;
}, false);
}, false);
<label>Click Me!
<input id="cb" type="checkbox" />
</label>
<label>Reflection:
<input id="rcb" type="checkbox" />
</label>
Here is code for checked and unchecked with a button:
var set=1;
var unset=0;
jQuery( function() {
$( '.checkAll' ).live('click', function() {
$( '.cb-element' ).each(function () {
if(set==1){ $( '.cb-element' ).attr('checked', true) unset=0; }
if(set==0){ $( '.cb-element' ).attr('checked', false); unset=1; }
});
set=unset;
});
});
Update: Here is the same code block using the newer Jquery 1.6+ prop method, which replaces attr:
var set=1;
var unset=0;
jQuery( function() {
$( '.checkAll' ).live('click', function() {
$( '.cb-element' ).each(function () {
if(set==1){ $( '.cb-element' ).prop('checked', true) unset=0; }
if(set==0){ $( '.cb-element' ).prop('checked', false); unset=1; }
});
set=unset;
});
});
Try this:
$('#checkboxid').get(0).checked = true; //For checking
$('#checkboxid').get(0).checked = false; //For unchecking
We can use elementObject with jQuery for getting the attribute checked:
$(objectElement).attr('checked');
We can use this for all jQuery versions without any error.
Update: Jquery 1.6+ has the new prop method which replaces attr, e.g.:
$(objectElement).prop('checked');
If you are using PhoneGap doing application development, and you have a value on the button that you want to show instantly, remember to do this
$('span.ui-[controlname]',$('[id]')).text("the value");
I found that without the span, the interface will not update no matter what you do.
Here is the code and demo for how to check multiple check boxes...
http://jsfiddle.net/tamilmani/z8TTt/
$("#check").on("click", function () {
var chk = document.getElementById('check').checked;
var arr = document.getElementsByTagName("input");
if (chk) {
for (var i in arr) {
if (arr[i].name == 'check') arr[i].checked = true;
}
} else {
for (var i in arr) {
if (arr[i].name == 'check') arr[i].checked = false;
}
}
});
Another possible solution:
var c = $("#checkboxid");
if (c.is(":checked")) {
$('#checkboxid').prop('checked', false);
} else {
$('#checkboxid').prop('checked', true);
}
As #livefree75 said:
jQuery 1.5.x and below
You can also extend the $.fn object with new methods:
(function($) {
$.fn.extend({
check : function() {
return this.filter(":radio, :checkbox").attr("checked", true);
},
uncheck : function() {
return this.filter(":radio, :checkbox").removeAttr("checked");
}
});
}(jQuery));
But in new versions of jQuery, we have to use something like this:
jQuery 1.6+
(function($) {
$.fn.extend({
check : function() {
return this.filter(":radio, :checkbox").prop("checked", true);
},
uncheck : function() {
return this.filter(":radio, :checkbox").prop("checked",false);
}
});
}(jQuery));
Then you can just do:
$(":checkbox").check();
$(":checkbox").uncheck();
If using mobile and you want the interface to update and show the checkbox as unchecked, use the following:
$("#checkbox1").prop('checked', false).checkboxradio("refresh");
For jQuery 1.6+
$('.myCheckbox').prop('checked', true);
$('.myCheckbox').prop('checked', false);
For jQuery 1.5.x and below
$('.myCheckbox').attr('checked', true);
$('.myCheckbox').attr('checked', false);
To check,
$('.myCheckbox').removeAttr('checked');
To check and uncheck
$('.myCheckbox').prop('checked', true);
$('.myCheckbox').prop('checked', false);
Be aware of memory leaks in Internet Explorer prior to Internet Explorer 9, as the jQuery documentation states:
In Internet Explorer prior to version 9, using .prop() to set a DOM
element property to anything other than a simple primitive value
(number, string, or boolean) can cause memory leaks if the property is
not removed (using .removeProp()) before the DOM element is removed
from the document. To safely set values on DOM objects without memory
leaks, use .data().
$('controlCheckBox').click(function(){
var temp = $(this).prop('checked');
$('controlledCheckBoxes').prop('checked', temp);
});
This is probably the shortest and easiest solution:
$(".myCheckBox")[0].checked = true;
or
$(".myCheckBox")[0].checked = false;
Even shorter would be:
$(".myCheckBox")[0].checked = !0;
$(".myCheckBox")[0].checked = !1;
Here is a jsFiddle as well.
Plain JavaScript is very simple and much less overhead:
var elements = document.getElementsByClassName('myCheckBox');
for(var i = 0; i < elements.length; i++)
{
elements[i].checked = true;
}
Example here
I couldn't get it working using:
$("#cb").prop('checked', 'true');
$("#cb").prop('checked', 'false');
Both true and false would check the checkbox. What worked for me was:
$("#cb").prop('checked', 'true'); // For checking
$("#cb").prop('checked', ''); // For unchecking
When you checked a checkbox like;
$('.className').attr('checked', 'checked')
it might not be enough. You should also call the function below;
$('.className').prop('checked', 'true')
Especially when you removed the checkbox checked attribute.
Here's the complete answer
using jQuery
I test it and it works 100% :D
// when the button (select_unit_button) is clicked it returns all the checed checkboxes values
$("#select_unit_button").on("click", function(e){
var arr = [];
$(':checkbox:checked').each(function(i){
arr[i] = $(this).val(); // u can get id or anything else
});
//console.log(arr); // u can test it using this in google chrome
});
In jQuery,
if($("#checkboxId").is(':checked')){
alert("Checked");
}
or
if($("#checkboxId").attr('checked')==true){
alert("Checked");
}
In JavaScript,
if (document.getElementById("checkboxID").checked){
alert("Checked");
}

Listen to objects click

I'm trying to listen to both "button" and "a" click, and then pass the value of the attribute "name" to a variable, I can't find what's wrong with my code:
$('a').click(function() {
var anchor;
anchor=$(this).attr('name');
$('#linkPressed').val(anchor);
});
$('button').click(function() {
var anchor;
anchor=$(this).attr('name');
$('#linkPressed').val(anchor);
});
Update: I have a PHP script that do something different according to the "linkPressed" value. Seemingly, this code is applicable also for <a> and <button> that don't have "name" attribute, which ruins my script. Is there a way to exclude the objects that don't have "name" attribute from the "click listener"?
To only select elements that have an attribute name, use the attribute selector:
$('a[name], button[name]').click(...);
// or
$('a, button').filter('[name]').click(...);
You can separate your selectors using comma ,. It's probably not working because you've initialize anchor variable two times:
$('a, button').click(function() {
var anchor;
anchor=$(this).attr('name');
$('#linkPressed').val(anchor);
});
You can bind the handler only to elements with name attributes:
$('a[name], button[name]').click(function() {
$('#linkPressed').val(this.name);
}
use multiple selector by the , at a one time it remove repetitive code
may be #linkPressed is a tag type not a input type at that time use text() at the palace of val()
$('a,button').click(function() {
var anchor;
anchor=$(this).attr('name');
$('#linkPressed').val(anchor);
});
I think this is it.
$("a, button").click(function() {
var anchor;
if($(this).attr("name") != undefined) {
anchor=$(this).attr('name');
$('#linkPressed').val(anchor);
}
});

Intercept value changes within .blur() event

I'm using .blur() function to execute some code every time a text field loses focus (also when its value doesn't change).
Now I need to add some logic that must be executed only when text field value changes. Is there a way to combine .change() event with .blur()? Or, better, is there a way to know if the value in my text field is changed just using .blur()?
Not directly, but you can store the value on focus event..
something like
$('input')
.on('focus',function(){
// store the value on focus
$(this).data('originalValue', this.value);
})
.on('blur',function(){
// retrieve the original value
var original = $(this).data('originalValue');
// and compare to the current one
if (original !== this.value){
// do what you want
}
});
Of course you could just bind different handlers for each event..
$('input')
.on('change', function(){/*your change code*/})
.on('blur', function(){/*your blur code*/});
The event change is trigger every time that the field lose the focus and the content has change. I think what you need is to use change() instead of blur(). Take a look at this jsfiddle
$('#in').change(function(){
alert('change!');
});
If what you need is to execute the same code when the input loses the focus and when the value changes, you can combine both events
$('in').on('change blur', function(){
//code
});
you can use closure to store the previous value and compare them later
var createOnBlurFunc = function(){
var prevVal = '';
return function(e){
if(prevVal === $(this).val()){
//same value
} else {
prevVal = $(this).val();
// do something
}
}
};
$('input').blur(createOnBlurFunc());
I think this is a more generalized way, for those that are created on the fly:
var $bodyEl = $('body'), inputOldValue;
$bodyEl.on('focus', 'input, textarea, select', function () {
inputOldValue = $(this).val();
});
$bodyEl.on('blur', 'input, textarea, select', function () {
if (inputOldValue != $(this).val()) {
$(this).trigger('changeBlur');
}
});
input, textarea, select is faster than :input as a selector.

Jquery Show Input Text Based On Input Value

I facing problem with my jquery, on showing input text based on input value.
Here is the JS fiddle demo :
http://jsfiddle.net/Ltapp/364/
When I try to input #hotmail, the input box will show. But when I want to type some text in the #hotm input box, it will hide again.
JS code :
$(window).load(function(){
var myString = '#hotmail';
$('#hotm').hide();
$("input").keyup(function () {
var value = $(this).val();
if($(this).val().match(myString)) {
$('#hotm').show();
} else {
$('#hotm').hide();
}
});
});
It's because your selector $("input") affects both input elements. I have updated it to the $("input:first") selector instead. JsFiddle here
$("input:first").keyup(function () {
var value = $(this).val();
if(value.match(myString)) {
$('#hotm').show();
} else {
$('#hotm').hide();
}
});
As many has said, you are binding the event on all the inputs I did a little change:
$(function(){
var myString = /#hotmail/ig;
$("#check").bind('keyup checkvalue', function() {
$('#hotm')[myString.test(this.value) ? 'show' : 'hide']();
}).trigger('checkvalue');
});
using regex if you are using #HoTmAil it will also hit on that, and also added a custom event checkvalue to see if #hotm should be visible on for example a postback on the form you might be using.
demo: http://jsfiddle.net/voigtan/xjwvT/1/
You're affecting all inputs. Either give each one a unique ID / Class or use the jQuery $(this) method.
See JSFiddle Here:
http://jsfiddle.net/Ltapp/366/
<input type="text" id="firstinput"/>
<p id="secondinput"><input type="text"/></p>
var myString = '#hotmail';
$('#secondinput').hide();
$("#firstinput").keyup(function () {
var value = $(this).val();
if($(this).val().match(myString)) {
$('#secondinput').show();
} else {
$('#secondinput').hide();
}
});
use this for your if part :
if($(this).val().match($(this).val().substr(0,strlen($(this).val())))
it's because the new box also = "input"; if you give the hotmail textbox it's own id, it won't hide
<input id="hotmail" type="text"/>
and then
$("#hotmail").keyup(function () {...});

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