Refer to immediate selector object with jQuery? - javascript

I'm trying to learn some jQuery, and I setup a test page with the following code:
<a id='encode' href='javascript: void(0)'>encode</a> |
<a id='decode' href='javascript: void(0)'>decode</a> |
<br/>
<textarea id='randomString' cols='100' rows='5'></textarea>
<script type='text/javascript'>
$(document.ready(function () {
$('#encode').click(function() {
$('#randomString').val(escape($('#randomString').val()));
});
$('#decode').click(function() {
$('#randomString').val(unescape($('#randomString').val()));
});
});
</script>
The idea is I can put something in the textarea and click either "encode" or "decode", and it will either escape or unescape what I put into the textarea.
This code works just fine, but my question has to do with how I am changing the value of the textarea. In my code, I am selecting the textarea value twice: once to (un)escape it, and once again to change the value. IMO this seems clunky and maybe unnecessary. I thought maybe I could do something like this instead:
$('#randomString').val(escape(this));
But this seems to refer to the object of the link I clicked, not the #randomString selector, so is there some other magic word I can use to reference that $('#randomString')?

$('#randomString').val(escape(this));
This does not get the object you want. It is effectively the equivalent of doing this:
var foo = escape(this);
$('#randomString').val(foo);
this only means something different when you start a new scope with a function definition.
jQuery does offer this kind of functionality with a callback option:
$('#randomString').val(function (idx, oldVal) {
return escape(oldVal);
});
The second parameter is the current value of the element; the return value sets a new value for the element.

You can try this
$(document.ready(function () {
$('#encode').click(function() {
var $randomString = $('#randomString');
$randomString.val(escape($randomString.val()));
});
$('#decode').click(function() {
var $randomString = $('#randomString');
$randomString.val(unescape($randomString.val()));
});
});

The short answer, if I understand you correctly, is no. There isn't a way to refer to $('#randomString') where you're talking about. It's just a parameter to the val method, so it's just plain JavaScript syntax, no jQuery "magic".
To accomplish the task at hand and make the code cleaner and less clunky, I would save off the jQuery object for #randomString so you don't have to keep creating it:
$(document.ready(function () {
var $rndStr = $('#randomString');
$('#encode').click(function() {
$rndStr.val(escape($rndStr.val()));
});
$('#decode').click(function() {
$('#rndStr').val(unescape($rndStr.val()));
});
});

You could make it a little generic:
$.fn.applyVal = function(func) {
return this.each(function() {
$(this).val( func( $(this).val() ) );
});
};
Then the following call is enough:
$('#randomString').applyVal(escape);

Related

Call single function for multiple classes

I have two buttons: one with class btn-star, and the other with btn-current. I am calling an independent function on each of their clicks. But now, I want to call only one function when they are called.
My code is similar to this:
$('document').ready(() => {
$(document).on('click', '.btn-star', function () {
// Do stuff
}
$(document).on('click', '.btn-current', function () {
// Do stuff
}
}
You can try this code. You can use multiple elements click event for one action with only one line code, Just use a comma for separating elements
$('document').ready(() => {
const myFunction= () => {
// Your Code here...
}
$(document).on('click', '.btn-current, .btn-current', function () {
myFunction();
}
}
You can define a function separately and pass it in as callback for both buttons' on click handler. For example -
$('document').ready(() => {
const commonFunc = () => {
// do common stuffs here
}
$(document).on('click', '.btn-star', commonFunc());
$(document).on('click', '.btn-current', commonFunc());
}
Hope that helps!
If you want to call the same function you can select your two button classes, using a simple j-query expression:
$('.btn-star, .btn-current').click(function() {
// Do stuff
}
Ad your selectors separated by a comma, inside the quotation marks.
You can read more about j-query selector at this link:
https://www.sitepoint.com/comprehensive-jquery-selectors/
A little shorter code...
$('document').ready(() => {
function commonFunc() {
//do stuffs here
}
$('.btn-star, .btn-current').on('click', commonFunc);
}
you can try like this:
function test()
{
//your code
}
$(".btn1, .btn2").on("click", funciton(){
test();
});
Try below code
$('.btn-star, .btn-current').on('click', function () {
// Do shared stuff
});
Reference: http://api.jquery.com/on/
Why is [Javascript] tagged on this post? If it is meant to be there, I'm assuming you are going to accept javascript responses right?
If you're going javascript, it is much easier, and you can just add a onClick='function()' to your html code and do your functions in there.
<html>
<head>
<script>
function buttonFunction(buttonName){
//EDIT 3.0: You can make one button do the same as the other button, but you can also make it do something else at the same time!
if(buttonName == 'btn-star'){
//other code such as:
alert("Stars are awesome!");
}
alert("You just clicked " + buttonName);
}
</script>
</head>
<body>
<div id='button1'>
<button id='btn-star' onclick='buttonFunction("btn-star")'>btn-star</button>
</div>
<br/>
<div id='button2'>
<button id='btc-current' onclick='buttonFunction("btn-current")'>btn-current</button>
</div>
</body>
</html>
If you want, you can also additionally make one button do the same as the other, and then after that do something different like I did in this snippet.
P.S: I'm just assuming javascript is allowed, because after all, it is tagged on this post.
EDIT: I showed you an example of one button doing slightly differently then the other, but still the same in a way
ANOTHER EDIT: You can do a lot of stuff with this, added ideas on what else you could do with this snippet.
You can try
$('.btn-star , .btn-current').on('click', function () {
//do something common for elements
});

Have the element who call my js function

I know my question have answer in the past but I don't have the vocabulary to find this.
I call a JavaScript function like this:
Voir +
This function change the state of the element .stats-table but I want to know which button have been clicked to call this function?
Better : can I have a jQuery object of this button?
Try to pass the this reference to know which button was clicked,
HTML:
Voir +
JS:
function showTable(selec,elem){
var currentElem = $(elem); //Clicked element
}
If you don't want to change the signature of the function and the way you invoke it (as others have suggested), you can use the global window.event to identify the clicked element:
function showTable(selector)
{
var clickedElement = window.event.target;
//...
}
See MDN.
When you use jQuery, you might consider refactor your code like this:
$(document).ready(function(){
$('.show-table-link').on('click', function(){
var $usedButton = $(this)
showTable('.stats-table')
}
})
Voir +
It's good practice to attach the on click handler instead of writing it inline. Further reading document.ready and jQuery event basics.
You can pass any value or id and your can identify the function
<script type="text/javascript">
function showTable(clss_name,fun_id)
{
if(fun_id=='A1')
{
alert("First function Executed");
}
if(fun_id=='A2')
{
alert("Second Function is executed");
}
}
</script>
......
......
......
Voir +
Voir2 +
If your function is like this:
function showTable(selec) {
// some code
}
You can get the clicked element like this, using this:
function showTable(selec) {
// some code
var clickedElem = this;
}

how to pass parameter in jquery using .on?

Good Day, this maybe a silly question :) how can I pass a parameter to an external javascript function using .on ?
view:
<script>
var attachedPo = 0;
$this.ready(function(){
$('.chckboxPo').on('ifChecked', addPoToBill(attachedPo));
$('.chckboxPo').on('ifUnchecked', removePoToBill(attachedPo ));
});
</script>
external script:
function addPoToBill(attachedPo){
attachedPo++;
}
function removePoToBill(attachedPo){
attachedPo--;
}
but Im getting an error! thanks for guiding :)
You need to wrap your handlers in anonymous functions:
$('.chckboxPo')
.on('ifChecked', function() {
addPoToBill(attachedPo);
})
.on('ifUnchecked', function() {
removePoToBill(attachedPo);
});
You can also chain the calls to on as they are being attached to the same element.
If your intention is to count how many boxes are checked, via passing variable indirectly to functions try using an object instead like this:
JSFiddle: http://jsfiddle.net/TrueBlueAussie/pBkhX/
var attachedPo = {
count: 0
};
$(function () {
$('.chckboxPo')
.on('change', function () {
if ($(this).is(':checked')) {
addPoToBill(attachedPo);
} else {
removePoToBill(attachedPo);
}
$("#output").prepend("" + attachedPo.count + "<br/>");
});
});
function addPoToBill(attachedPo) {
attachedPo.count++;
}
function removePoToBill(attachedPo) {
attachedPo.count--;
}
If it is not doing anything else you can simplify the whole thing to count checked checkboxes:
$(function () {
var attachedPo = 0;
$('.chckboxPo')
.on('change', function () {
attachedPo = $(".chckboxPo:checked").length;
});
});
"DOM Ready" events:
you also needed to wrap it in a ready handler like this instead of what you have now:
$(function(){
...
});
*Note: $(function(){YOUR CODE HERE}); is just a shortcut for $(document).ready(function(){YOUR CODE HERE});
You can also do the "safer version" (that ensures a locally scoped $) like this:
jQuery(function($){
...
});
This works because jQuery passes a reference to itself through as the first parameter when your "on load" anonymous function is called.
There are other variations to avoid conflicts with other libraries (not very common as most modern libs know to leave $ to jQuery nowadays). Just look up jQuery.noConflict to find out more.

Appending existing onClick value

I am using javascript and need to grab the value of an existing onclick and append to it. I am not trying to replace the current onclick, I am trying to append to the front, or end, of it. But all different iterations of this effort are failing.
Quick example:
<pre>
<a href="blah" id="tabA" onclick="alert("this");"
<script>
function test() {
alert("that") ;
}
document.getElementById('tabA').onclick = "test();" + document.getElementById('tabA').getAttribute('onclick') ;
</script>
</pre>
When using the .onclick event you should use function and then the action:
document.getElementById("tabA").onclick = function()
{
alert("hello world")//this will work
}
document.getElementById('tabA').onclick = "test();" + document.getElementById('tabA').getAttribute('onclick') ;//fail since events are not variables to store values.
So, what you whatever you are tring to do, in that way it wont work.
I don't know if I had got your point.
My solution is
tabA
<script>
function test() {
alert("that") ;
}
var oldClick = document.getElementById('tabA').getAttribute('onclick') ;
var newClick = function(){
test();
eval(oldClick);
}
document.getElementById('tabA').onclick = newClick;
</script>
when I click the 'tabA', it alerts 'that' then 'this'.
http://jsfiddle.net/x3Xds/
I know this is quite old but, I needed to do the same thing.
I got around this by using an event;
obj.addEventListener('click', function(){ test(); }, false);

Unexpected jQuery syntax error by chaining a plug-in after .find()

I've baked a plug-in to handle runtime searches on input fields I'm using all over a big site.The plug-in works perfect in every situation but this http://jsfiddle.net/tonino/v8d2A/
$(document).ready(function () {
var callback_methods = { /* methods here */ };
var input_html = '<div class="search"><input name="search-field" value="Search..."></div>';
$(document).on('click', 'div.add', function (event) {
if (!$('li div.add + div').hasClass('search')) {
var input = $(this).after(input_html).parent().find('input');
input.focus();
input.hunter({url:'<?php echo $this->request->base; ?>/searches', callback:callback_methods, var_name:'data[Search][term]'});
// other code after
}
});
});​
If I comment the hunter plug-in everything works fine.
I'm sure is some concept on how it must be structured, here is the code: jquery.hunter.1.3.js
Why my plug-in make this error in this situation, where I'm wrong on writing it?
the problem is this part of your code:
var selector = this.selector;
var def_css = {backgroundPosition:'-16px center', paddingLeft:$(selector).css('padding-left')}
if (settings.loader) { setStyle(def_css); }
var selector = this.selector;
and later:
$(this.selector).blur(function () {
first of all your code wont work when the if-condition is fulfilled, because you are trying to redeclare the variable 'selector' inside the if block. just leave the var-statement out there:
if (settings.loader) { setStyle(def_css); }
selector = this.selector;
but YOUR MAIN-problem is that 'this.selector' contains '.parent() input' which i doubt is a valid jQuery selector.
why are you doing that? why dont you just use $(this) save it into a variable and use this???
eg:
// first line in your plugin
$this = $(this)
// later you could use the $this var
$this.blur(function () {
To get rid of the error change this line:
var input = $(this).after(input_html).parent().find('input');
To the following:
var input = $(input_html).insertAfter($(this));
The core problem though is that the jquery.hunter plugin is using the this.selector variable for some reason - you don't need this - the plugin should use $(this) instead of $(this.selector)

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