Develop Reference

How to find and add the function to id?

I want to add a function to the attribute onChange of the element with id="custom-taxonomy". I don't want to edit the file.
I want to have a javascript solution.
My idea is to find the element by the id and then add the function.
How can i achiev this idea?
The code:
<div id ="custom-taxonomy">PRODUCT PRICES</div>
Expected result:
<div id ="custom-taxonomy" name="custom-product" onchange="return chothuephuongxa();>PRODUCT PRICES</div>

you can do that using setAttribute() and document.getElementById
let elm = document.getElementById('custom-taxonomy')
elm.setAttribute('name',"custom-product")
elm.setAttribute("onclick","return chothuephuongxa();")
console.log(elm.outerHTML)
<div id ="custom-taxonomy">PRODUCT PRICES</div>
Note:
You can't use name attribute of <div> but using elm.name = ... because name property in not available on <div> elements.
Similarly elm.onclick = "return chothuephuongxa();" is not correct because this will set event to string instead of function

You can use setAttribute to add attributes to elements:
document.getElementById('custom-taxonomy').setAttribute('name', 'custom-product');
the same can be done for your event.

Getting the value of an input element in jquery

I would like to get the value of a input using a the a chain class as the identifier in jquery. is this possible?
I have the following code
<input class="donate-block__value monthly" type="text" id="donation-amount" name="DonationAmount" value="200" />
and i have tried the following which has resulted in undefined
var monthlyDonation = $('.donate-block__value .monthly').val();
var monthlyDonation = $('donate-block__value monthly').val();
console.log(monthlyDonation);
I need to target the class Can this be done please?

Don't add space between your classes or jquery will start to search within the first class looking for a child element. use it like this:
var monthlyDonation = $('.donate-block__value.monthly').val();

You can also target just the input element in case you have multiple elements with that class defined:
$('input.donate-block__value.monthly').val();

Your selector .donate-block__value .monthly is referring to an element within an element. Try just .donate-block__value or .monthly

How to clone elements and generate dynamic ids

I am cloning some form elements and want to generate for them dynamic ids so I can acces their content later on, but I don't really know how to do that, I'm a noob with Jquery/Javascript, by the way.
My html:
<tr>
<td>
<label for="ability">Ability</label><br>
<div id="rank_ability" name="rank_ability">
<select name="ability" id="ability">
<option value=""></option>
<option value="hexa">Test</option>
</select><br>
<label for="range_ability_min">Range:</label>
<input type="textbox" name="range_ability_min" id="range_ability_min" class="small_text" value="0" /> -
<input type="textbox" mame="range_ability_max" id="range_ability_max" class="small_text" value="0" /><br>
</div>
Add Ability<br><br>
</td>
</tr>
My JS:
$(document).ready(function () {
var element, ele_nr, new_id;
$('.rank_clone').click( function() {
element = $(this).prev();
ele_nr = $('div[name="'+element.attr('name')+'"]').length;
new_id = element.attr('name') + ele_nr;
element.clone().attr('id', new_id).attr('name', new_id).insertAfter(element);
});
});
I setup a jsfiddle with what I got here: http://jsfiddle.net/xjoo4q96/
Now, I am using .prev() to select the element to clone which leads to those repeated 1 in the id/name attributes, how could I select it in another way (to mention: I really need to use 'this' because I need this little script in like 3 places, so I don't want to write it for an element with a specific id/class).
Also, I am counting only the element with the base name attribute so .lenght yelds 1 all the time, how would I go around counting all of them ? I guess I have to place them in another div or something but I don't know how would I go around couting them even then.
And, at last, how would I go around changing all the name/id attributes of the elements I have in the div ?
I'd appreciate any help. Thanks.

you can put the template in a hidden div like #tmpl, then clone and set the id attr, e.g.
$('#tmpl').children().first().clone().appendTo('#target').attr('id', 'the_generated_id');
Update
Demo of the template way: http://jsfiddle.net/xjoo4q96/1/, though it would be quite easy to adjust the code to clone the first component that already existed.
BTW, principally, id should be unique, thus the sub-element in the cloned component should use other attribute, like class or certain data- attribute, like those used in the updated fiddle.
Also you might want to call event.preventDefault() as you're clicking an <a>

You are searching already with the wrong name, since it still has the number attached. So delete it first, search for element which have a name attribute starting with this name and then use this base name to create a new one.
$(document).ready(function () {
var element, ele_nr, new_id, base_name;
$('.rank_clone').click( function() {
element = $(this).prev();
base_name = element.attr('name').replace(/[0-9]/g, '');
ele_nr = $('div[name^="'+base_name+'"]').length;
new_id = base_name + ele_nr;
element.clone().attr('id', new_id).attr('name', new_id).insertAfter(element);
});
});
And to answer your last question: you can not go around changing all ids of inner elements, it would be invalid HTML. In principal you can do the same with every id, like adding a number. If you have to do the same with all the name attributes depends on what you want to do exactly. If you have to distinguish between the first and second input, which I suggest, you have to change them too.

try to use cloneJs, it's clone ids, names input, and parametre inside functions ids of input must be like id_foo_1, id_foo_2 ,,,, and name be like inputName[0][foo], inputName[1][foo] https://github.com/yagami271/clonejs

Referencing the HTML select control currently being used

I have a javascript program to filter a list of things in a HTML select control by typing a regular expression into an input (text) box. I can do the following to correctly filter a specific select control:
$(function() {
$('input[data-filterable]').keyup(
function() {
filter = new filterlist(document.myform.myselect);
filter.set(this.value);
});
});
but I have used a custom attribute (something one can now do in HTML5) called data-filterable. The attribute will store the name of the select control that is to be filtered so that JS can use the name of the control to filter the list. This would be a good idea because I will have a general function to filter any select box rather than a specific one.
Any ideas how I do this? I need something like this in the HTML:
<input data-filterable='{"to":"#selectbox1"}' size="30" type="text" />
but I'm not sure exactly what I'm doing here and what to do with the JS.
Thanks guys :).

Try this:
<input data-filterable="#selectbox1" size="30" type="text" />
$(function() {
$('input[data-filterable]').keyup(
function() {
filter = new filterlist($($(this).data('filterable'))[0]);
filter.set(this.value);
});
});
To break down the expression $($(this).data('filterable'))[0]:
$(this) wraps this in a jQuery wrapper. In our context, since it's a jQuery keyup event handler, this references the <input> DOM node.
$(this).data('filterable') retrieves the contents of the data-filterable attribute as a string. In our case, it's #selectbox1.
After that this string gets passed in to jQuery as a selector: $($(this).data('filterable')).
Finally, we take the 0'th element of the returned array which should be the DOM element of the target selectbox. Of course, if there isn't a selectbox which fits the selector this will fail rather miserably. If you suspect that this is a real scenario, check the .length of the returned array first.

How to access HTML of a Input element

Hi I am trying to get the HTML of INPUT tag. But unable to..
<input type="checkbox" name="_QS4_CNA" id="_Q0_C7" class="mrMultiple" value="NA">
<label for="_Q0_C7">
<span class="mrMultipleText" style="">None of these</span>
</label>
</input>
And I am trying access as
var dat=$(':checkbox#_Q0_C7').html();
alert(dat);
But i cannot access this. Please help me on this..

The ".html()" method gets the contents of an element, and not the element itself. In your case, the problem is that your HTML is invalid. An <input> tag cannot have content. As far as the browser is concerned, the tag ends where the <label> tag starts, and the browser just ignores the closing tag.
Note that when you've got an "id" attribute to use to find an element, you don't need any other qualifiers in the selector (like ":checkbox"). Just "#_Q0_C7" is all you need, because "id" values have to be unique anyway.
edit — Note that if all you want is to get some attribute (like the value or the "checked" status) from the element, you can certainly do that:
var $cb = $('#_Q0_C7');
var isChecked = !!$cb.prop('checked'); // force a real boolean value
var value = $cb.val();

You can try accessing the RAW underlying DOM element and use its innerHTML property.
var dat = $(":checkbox#_Q0_C7")[0].innerHTML;
But like mentioned by Pointy, that might still get you nothing. Not sure what (if any) input elements have actual siblings.