I feel like I already know the answer to this is going to be "not possible" but just in case.
Let's say I have this javascript function used to read .net webform field's value:
function getById(theId) {
return document.getElementById(theId).value;
}
which I can call like this:
getById("<%=txtField1.ClientID%>");
Ok, that works fine.
But it is a given that .ClientID is always going to be in there, which means this function could be whittled down, but only if it is possible to represent the form field as a variable by itself. Something like this:
function getById(fieldName) {
return document.getElementById(<%= + fieldName + .ClientID%>).value;
}
to be called like this (much cleaner)...
getById("txtField1");
Is this possible?
Well yes and no/maybe.
Yes Part:
JS order of operations supports the ability to append strings before the get element call. For example if I had a textbox with id "searchTerm" then I could do this in js and be absolutely fine:
var check = document.getElementById('search' + 'Term').value;
NO Part: unless webforms differs significantly than what I remember way back when, that original function you have there is created to specifically get values when js is called inline and is about as optimized as you are going to get for that action. Once the page is loaded all of those server side variables will no longer be available for javascript and you would have to use the true client side elements IDs. Once workaround I suppose is to add onClick action to pass the client side ID such like so
<input type="text" onClick="WhatIsLove(this.id)" value="BabyDontHurtMe" id="Sing">
I have a bunch of dropdownlists that are filled dynamically with Jquery but i'm trying to convert them to Asp:DropDownLists instead of actual pure HTML select dropdowns so i can access and manipulate their values directly from the server side more easily (so i can save the Session value) instead of having to use the Request.Form command. Since the Asp:DropDownList class has it's particularities, i had to adapt the code i had including the Javascript/Jquery functions which access the drops and fill them (all of their ids share a similar nomenclature but with a different number at the end). However, when i try to access the ID, this doesn't seem to work:
$('#<%= select_plan_'+i+'.ClientID %>')
I always seem to get this compilation error:
CS1026: ) expected
The "i" has to be there since i'm using a "for" loop to go through all of the drops and fill them. Like i mentioned, all of the drops's ids share a similar nomenclature but with a different number at the end.
This is how one of the drops is defined:
<asp:DropDownList runat=server id="select_plan_4" onchange=ChangePrice(this,4);SetSelectedText(4); name=select_plan_4>
...
</asp:DropDownList>
Anyway, how can i get over this issue? Is there a better alternative? Thanks in advance!
UPDATE: Js function code added.
function ChangePlan(n, control) {
family = decodeURIComponent(window.location.search).split('=')[1];
$('#select_plan_'+n).find('option').remove().end();
for (var i = 1; i < data.length-1; i++) {
var aux = data[i].split(';');
if (aux[0] == family) {
var html='<asp:ListItem Value="'+aux[control]+'" Text="'+aux[1]+'" >'+ aux[1] +'</asp:ListItem>';
$('#select_plan_'+n).append(html);
}
}
}
Have a look at the rendered HTML of your page in the Dev Tools for your browser (e.g. by pressing F12 when using Chrome). You'll see that usually the controls, when they're actually rendered, don't have the IDs you've assigned them.
You need to find the actual ID of the rendered control. For a good description of a few techniques for doing this, check out this blog post.
I'm writing a small plugin for ckeditor,
On a button firing, I'm trying to make the editor grab the raw html data to send to the server.
The correct syntax for this is
CKEDITOR.instances.div_id.getData();
or alternatively
CKEDITOR.instances[div_id].getData();
However this is grabbing a set named id, I want it to be relative to its parent id
var id = $(this).parent().attr("id");
var htmlcontent = CKEDITOR.instances.id.getData();
I'm realizing I don't know how to plug a var in that without thinking it's a function falling under CKEDITOR. I should know this but it's just not coming to me.
Anecdotally that might not be a working parent id-grabber
EDIT: To solve the CKeditor issue (which is not easy to find on the net)
CKeditor has some built in API to grab the container element id.
This is a working id-grabber for a CKeditor plugin and the data-grab syntax helped constructed by the answers below:
var id = editor.container.getId();
var htmlcontent = CKEDITOR.instances[id].getData();
as of 12/4/2014
Why doesn't var htmlcontent = CKEDITOR.instances.id.getData(); work? The reason is that id is a variable holding the exact id stored previously in the line
var id = $(this).parent().attr("id");
This id variable holds something like "myElementId" in it. In order for you to use that string, you need to access the instances object using "bracket notation" (Related: Working with Objects MDN) if you do not specifically know the name of "myElementId" in advance.
As a result, this will work
var htmlcontent = CKEDITOR.instances[id].getData();
And would be similar to CKEDITOR.instances.myElementId.getData() if "myElementId" was the id of the parent element previously stored.
If you already have an editor object, you don't need to use CKEDITOR.instances at all, just use
editor.getData();
So, I have some code that should do four things:
remove the ".mp4" extension from every title
change my video category
put the same description in all of the videos
put the same keywords in all of the videos
Note: All of this would be done on the YouTube upload page. I'm using Greasemonkey in Mozilla Firefox.
I wrote this, but my question is: how do I change the HTML title in the actual HTML page to the new title (which is a Javascript variable)?
This is my code:
function remove_mp4()
{
var title = document.getElementsByName("title").value;
var new_title = title.replace(title.match(".mp4"), "");
}
function add_description()
{
var description = document.getElementsByName("description").value;
var new_description = "Subscribe."
}
function add_keywords()
{
var keywords = document.getElementsByName("keywords").value;
var new_keywords = prompt("Enter keywords.", "");
}
function change_category()
{
var category = document.getElementsByName("category").value;
var new_category = "<option value="27">Education</option>"
}
remove_mp4();
add_description();
add_keywords();
change_category();
Note: If you see any mistakes in the JavaScript code, please let me know.
Note 2: If you wonder why I stored the current HTML values in variables, that's because I think I will have to use them in order to replace HTML values (I may be wrong).
A lot of things have been covered already, but still i would like to remind you that if you are looking for cross browser compatibility innerHTML won't be enough, as you may need innerText too or textContent to tackle some old versions of IE or even using some other way to modify the content of an element.
As a side note innerHTML is considered from a great majority of people as deprecated though some others still use it. (i'm not here to debate about is it good or not to use it but this is just a little remark for you to checkabout)
Regarding remarks, i would suggest minimizing the number of functions you create by creating some more generic versions for editing or adding purposes, eg you could do the following :
/*
* #param $affectedElements the collection of elements to be changed
* #param $attribute here means the attribute to be added to each of those elements
* #param $attributeValue the value of that attribute
*/
function add($affectedElements, $attribute, $attributeValue){
for(int i=0; i<$affectedElements.length; i++){
($affectedElements[i]).setAttribute($attribute, $attributeValue);
}
}
If you use a global function to do the work for you, not only your coce is gonna be easier to maintain but also you'll avoid fetching for elements in the DOM many many times, which will considerably make your script run faster. For example, in your previous code you fetch the DOM for a set of specific elements before you can add a value to them, in other words everytime your function is executed you'll have to go through the whole DOM to retrieve your elements, while if you just fetch your elements once then store in a var and just pass them to a function that's focusing on adding or changing only, you're clearly avoiding some repetitive tasks to be done.
Concerning the last function i think code is still incomplete, but i would suggest you use the built in methods for manipulating HTMLOption stuff, if i remember well, using plain JavaScript you'll find yourself typing this :
var category = document.getElem.... . options[put-index-here];
//JavaScript also lets you create <option> elements with the Option() constructor
Anyway, my point is that you would better use JavaScript's available methods to do the work instead of relying on innerHTML fpr anything you may need, i know innerHTML is the simplest and fastest way to get your work done, but if i can say it's like if you built a whole HTML page using and tags only instead of using various semantic tags that would help make everything clearer.
As a last point for future use, if you're interested by jQuery, this will give you a different way to manipulate your DOM through CSS selectors in a much more advanced way than plain JavaScript can do.
you can check out this link too :
replacement for innerHTML
I assume that your question is only about the title changing, and not about the rest; also, I assume you mean changing all elements in the document that have "title" as name attribute, and not the document title.
In that case, you could indeed use document.getElementsByName("title").
To handle the name="title" elements, you could do:
titleElems=document.getElementsByName("title");
for(i=0;i<titleElems.length;i++){
titleInner=titleElems[i].innerHTML;
titleElems[i].innerHTML=titleInner.replace(titleInner.match(".mp4"), "");
}
For the name="description" element, use this: (assuming there's only one name="description" element on the page, or you want the first one)
document.getElementsByName("description")[0].value="Subscribe.";
I wasn't really sure about the keywords (I haven't got a YouTube page in front of me right now), so this assumes it's a text field/area just like the description:
document.getElementsByName("keywords")[0].value=prompt("Please enter keywords:","");
Again, based on your question which just sets the .value of the category thingy:
document.getElementsByName("description")[0].value="<option value='27'>Education</option>";
At the last one, though, note that I changed the "27" into '27': you can't put double quotes inside a double-quoted string assuming they're handled just like any other character :)
Did this help a little more? :)
Sry, but your question is not quite clear. What exactly is your HTML title that you are referring to?
If it's an element that you wish to modify, use this :
element.setAttribute('title', 'new-title-here');
If you want to modify the window title (shown in the browser tab), you can do the following :
document.title = "the new title";
You've reading elements from .value property, so you should write back it too:
document.getElementsByName("title").value = new_title
If you are refering to changing text content in an element called title try using innerHTML
var title = document.getElementsByName("title").value;
document.getElementsByName("title").innerHTML = title.replace(title.match(".mp4"), "");
source: https://developer.mozilla.org/en-US/docs/DOM/element.innerHTML
The <title> element is an invisible one, it is only displayed indirectly - in the window or tab title. This means that you want to change whatever is displayed in the window/tab title and not the HTML code itself. You can do this by changing the document.title property:
function remove_mp4()
{
document.title = document.title.replace(title.match(".mp4"), "");
}
I use this code to get value from an input box:
var suggest_type = document.getElementById('ac-type').value;
Now I need to apply my js code on several other pages. I heard that it's not nice to repeat an ID on one website. So, I'm thinking to change to use class like this:
var suggest_type = document.getElementByClass('ac-type').value;
This doesn't get the value. How can I use class to get value?
You should stick with using ID's - they only have to be unique within a page.
If you must use classes, you need to use getElementsByClassName():
var elems = document.getElementsByClassName('ac-type');
var value = elems[0].value;
However this function is not well supported on older browsers, which is another good reason to stick with IDs.
Its absolutely fine to repeat ids across a website just not on a single html document.
ID's should be unique within one html page.
It's actually :
var suggest_type = document.getElementsByClassName('ac-type')[0].value;
But I agree with Jon Taylor, ID's can be the same within a website, as long they are not duplicated on the same page.
try using this:
var elements = document.getElementsByClassName('ac-type'); // this is an array containing all matched elements
Use jquery just by using -
$('.ac-type').val();
you will get value.