Writing to a non-unique div with Javascript - javascript

I'm building a multi-feed RSS reader for school.
aList is the div that encompasses each individual feed (the amount of feeds will fluctuate).
theTitle is the div that will be filled with the attribute of the current feed. Additionally, if clicked, it will load a list of attributes from the current feed into theContent.
I'm wondering how I can dynamically load the attributes into theContent when theTitle is clicked, since theContent and theTitle are going to be non-unique divs (I can't give them IDs).
Thanks for your help in advance,
-Andrew

document.getElementsByClassName('aList').getElementsByTagName('div')

You should look into jQuery selectors for that and other DOM Manipulation. Something like
$("div.theContent").attr("name", "value");

by using jquery, you may use code like the following:
$(".theTitle").bind("click", function(){
$el = $(this);
$el.parent().$(".theContent").load('ajax/content.php?news=' . $el.text());
});
this will make all your links clickable, an on click, update their corresponding content divs with the value of ajax/content.php?news=theTitle-value

Use a nice Javascript library such as Prototype or jQuery. Seems petty now, but these frameworks save you tons of time in the long run.
In both frameworks, you can select that div with:
$('div.theTitle')
With jQuery, you can do:
$('div.theTitle').click( function() {
var title = $(this).text();
var contentDiv = $(this).siblings('div.theContent');
// Do something with contentDiv and the title
} );
This will make every theTitle div have an onClick event that does something with its associated theContent div.

<div class="aList">
<div class="theTitle" onclick="fillContentBox(this)"></div>
<div class="theContent"></div>
</div>
And in your script ...
function fillContentBox(div) {
var theContentDiv = div.parentNode.getElementsByTagName("div")[1];
// statements that do things with theContentDiv
}

You have to be able to determine which element you want to update if you don't want to update more than one. If the elements are grouped inside something else that does have an "id" value, you can take advantage of that.

Related

show all the values with .html [duplicate]

Lets say I have an empty div:
<div id='myDiv'></div>
Is this:
$('#myDiv').html("<div id='mySecondDiv'></div>");
The same as:
var mySecondDiv=$("<div id='mySecondDiv'></div>");
$('#myDiv').append(mySecondDiv);
Whenever you pass a string of HTML to any of jQuery's methods, this is what happens:
A temporary element is created, let's call it x. x's innerHTML is set to the string of HTML that you've passed. Then jQuery will transfer each of the produced nodes (that is, x's childNodes) over to a newly created document fragment, which it will then cache for next time. It will then return the fragment's childNodes as a fresh DOM collection.
Note that it's actually a lot more complicated than that, as jQuery does a bunch of cross-browser checks and various other optimisations. E.g. if you pass just <div></div> to jQuery(), jQuery will take a shortcut and simply do document.createElement('div').
EDIT: To see the sheer quantity of checks that jQuery performs, have a look here, here and here.
innerHTML is generally the faster approach, although don't let that govern what you do all the time. jQuery's approach isn't quite as simple as element.innerHTML = ... -- as I mentioned, there are a bunch of checks and optimisations occurring.
The correct technique depends heavily on the situation. If you want to create a large number of identical elements, then the last thing you want to do is create a massive loop, creating a new jQuery object on every iteration. E.g. the quickest way to create 100 divs with jQuery:
jQuery(Array(101).join('<div></div>'));
There are also issues of readability and maintenance to take into account.
This:
$('<div id="' + someID + '" class="foobar">' + content + '</div>');
... is a lot harder to maintain than this:
$('<div/>', {
id: someID,
className: 'foobar',
html: content
});
They are not the same. The first one replaces the HTML without creating another jQuery object first. The second creates an additional jQuery wrapper for the second div, then appends it to the first.
One jQuery Wrapper (per example):
$("#myDiv").html('<div id="mySecondDiv"></div>');
$("#myDiv").append('<div id="mySecondDiv"></div>');
Two jQuery Wrappers (per example):
var mySecondDiv=$('<div id="mySecondDiv"></div>');
$('#myDiv').html(mySecondDiv);
var mySecondDiv=$('<div id="mySecondDiv"></div>');
$('#myDiv').append(mySecondDiv);
You have a few different use cases going on. If you want to replace the content, .html is a great call since its the equivalent of innerHTML = "...". However, if you just want to append content, the extra $() wrapper set is unneeded.
Only use two wrappers if you need to manipulate the added div later on. Even in that case, you still might only need to use one:
var mySecondDiv = $("<div id='mySecondDiv'></div>").appendTo("#myDiv");
// other code here
mySecondDiv.hide();
if by .add you mean .append, then the result is the same if #myDiv is empty.
is the performance the same? dont know.
.html(x) ends up doing the same thing as .empty().append(x)
Well, .html() uses .innerHTML which is faster than DOM creation.
.html() will replace everything.
.append() will just append at the end.
You can get the second method to achieve the same effect by:
var mySecondDiv = $('<div></div>');
$(mySecondDiv).find('div').attr('id', 'mySecondDiv');
$('#myDiv').append(mySecondDiv);
Luca mentioned that html() just inserts hte HTML which results in faster performance.
In some occassions though, you would opt for the second option, consider:
// Clumsy string concat, error prone
$('#myDiv').html("<div style='width:'" + myWidth + "'px'>Lorem ipsum</div>");
// Isn't this a lot cleaner? (though longer)
var newDiv = $('<div></div>');
$(newDiv).find('div').css('width', myWidth);
$('#myDiv').append(newDiv);
Other than the given answers, in the case that you have something like this:
<div id="test">
<input type="file" name="file0" onchange="changed()">
</div>
<script type="text/javascript">
var isAllowed = true;
function changed()
{
if (isAllowed)
{
var tmpHTML = $('#test').html();
tmpHTML += "<input type=\"file\" name=\"file1\" onchange=\"changed()\">";
$('#test').html(tmpHTML);
isAllowed = false;
}
}
</script>
meaning that you want to automatically add one more file upload if any files were uploaded, the mentioned code will not work, because after the file is uploaded, the first file-upload element will be recreated and therefore the uploaded file will be wiped from it. You should use .append() instead:
function changed()
{
if (isAllowed)
{
var tmpHTML = "<input type=\"file\" name=\"file1\" onchange=\"changed()\">";
$('#test').append(tmpHTML);
isAllowed = false;
}
}
This has happened to me . Jquery version : 3.3.
If you are looping through a list of objects, and want to add each object as a child of some parent dom element, then .html and .append will behave very different. .html will end up adding only the last object to the parent element, whereas .append will add all the list objects as children of the parent element.

Creating dynamic divs

Trying to make a dynamic div but i don't know how. Wrote a solidity smart contract that accepts an array of struct. In the smart contract i can use a get function to display the data inside. Data in the array is treated like a history, it consists of amount (making a crowdfund site), date, currency used, etc. Since the get function in the smart contract can only extract one part of the array, i thought of putting the get function into the while loop and extract the whole history array..
<div id=set>
<a>value1</a>
<a>value2</a>
</div>
I'm trying to dynamically create another div with the same amount of < a > in the div. If i had 10 sets of data to display in that div, i wish to create only 10 sets of that div. Can createElement() be used to do that? Couldn't find any solution that works. Totally have no idea on how to create it. Can someone please help.
Would it be rational to extract the data from the array using a while loop and putting it in a div to display or would it use too much gas for this to work?
I don't get why would you want to do this, but you can do like this:
$('#set a').each(function(){
$('#set').after( "<div></div>");
});
It selects all of the <a>...</a> inside the <div id="set">...</div> element, and for each one of those inserts a <div></div> element. It inserts the element right next to #set but you can change that to any other element you could select.
I'm supplying jQuery code since you tagged the question as jQuery.
Hope it helps,
You can get the number of anchor tags by using this function getElementsByTagName('a').length from the hosting div. Then use that number to create new divs. This solution is done using vanilla JS.
function createDynamicDivs(){
var newDiv = document.createElement("div");
var noOfAnchors = document.getElementById('set').getElementsByTagName('a').length;
for(var i=0;i<noOfAnchors;i++){
var newContent = document.createElement("a");
newContent.textContent= "Test ";
newDiv.appendChild(newContent);
}
document.getElementById('new').appendChild(newDiv);
}
<div id=set>
<a>value1</a>
<a>value2</a>
</div>
<div id="new"></div>
<button onclick="createDynamicDivs()">Generate</button>

jQuery + JSON - .each not retrieving unique values

This is my codepen: http://codepen.io/JTBennett/pen/OpEeBG
This is the jQuery in question:
$('.gvListing').each(function(){
var cntTxt = $('.dispCntry').text()
$(this).attr('data-country',cntTxt)
var valueC = $('.ddCountry:selected').val();
var valueR = $('.ddRegion:selected').val();
$('#testDiv').text(valueC)
});
(^this all happens at the bottom of the JS on the codepen link)
The issue looks like this:
So the data attribute is being filled up with every .dispCntry div's contents even though I'm doing this function in .each() .gvListing div. I have a feeling I'm missing something stupid, like the letter i somewhere - but I can't seem to get it right.
var cntText=$('.dispCntry').text();
will take every text of input that has .dispCntry class.
It does not concentrate on your .each() .gvListing div.
Either you have to use only one .dispCntry class input, or give unique class or id to each .dispCntry elements

Wrapping a jquery validate span.error with nested divs

Heyo. This is my first stack overflow post because I am stumped and not finding many people who are trying to accomplish the same thing. I've tried using jquery .before(), .after(), and .wrap() to resolve this. I was initially using css :before and :after pseudo-elements, but as that won't work for legacy browsers, I've decided to use jquery.
I already have several forms on several pages with validation working. The error messages vary in length. We were using a static, one size background image on the default span element, so content was bleeding out on longer error messages. I built a flexible rounded corner series of nested divs to allow the error box to grow or shrink dynamically. The html I want to output is:
<div class="errorWrap">
<div class="errorTop"><span></span></div>
<div class="errorContent">
<span class="error">This is an error</span>
</div>
<div class="errorBottom"><span></span></div>
</div>
Here's an example of a solution I tried, but I'm still pretty new to javascript.
$('.error').before('<div class="errorWrap"><div class="errorTop"><span></span></div><div class="errorContent">');
$('.error').after('</div><div class="errorBottom"><span></span></div></div>');
Correct me if I'm wrong, but I think that I have the right idea with the jquery. But it's just kind of sitting there, not in any function being called. So I imagine that since the code isn't re-executing, it just doesn't show up. Is there an appropriate function to wrap this in? I'm certain I'm just not attacking this from the right direction. Any help is super appreciated.
the plugins "before" and "after" dont take html as string. you cannot start a div in one and close it in an other.
Either you take your current html and generate a new html string which you append where you want to or you use the "wrap" plugin http://api.jquery.com/wrap/
Using pure HTML
$(".error").html("<div class='beforeContent'>" + $(".error").html() + "</div>");
Using wrap (http://api.jquery.com/wrap/)
$(".error").wrap("<div class='beforeAndAfter'></div>");
If you want to show an error div after focus out of an input then you have to create it using html/wrap as Luke said and then you have to append it in ot the dom useing
$('.errorWrap').insertAfter('.focusedElement');
But there are other methods available to insert a new element like append/appendTo e.t.c,
I ended up fixing this problem on my own using jquery to create the div and it's nesting on pageload, the divs are generated with an error class that gives display:none. A custom errorPlacement function nests the error in the correct div. Then I used a custom validator highlight function to remove the class that hides the element. Then I used the unhighlight function to re-add the class to re-hide the div.
$(function() {
//Generate the elements and assign attributes
var errorWrap = document.createElement('div');
$(errorWrap).addClass('errorWrap hideError');
var errorTop = document.createElement('div');
$(errorTop).addClass('errorTop');
var topSpan = document.createElement('span');
var errorContent = document.createElement('div');
$(errorContent).addClass('errorContent');
var errorBottom = document.createElement('div');
$(errorBottom).addClass('errorBottom');
var bottomSpan = document.createElement('span');
//Place the elements directly after each dd element
$("dl > dd").append(errorWrap);
$("div.errorWrap").append(errorTop)
.append(errorContent)
.append(errorBottom);
$("div.errorTop").append(topSpan);
$("div.errorBottom").append(bottomSpan);
//Add custom validator defaults
$.validator.setDefaults({
errorPlacement: function(error, element) {
$(element).nextAll('.errorWrap').children('.errorContent').append(error);
},
highlight: function(element) {
$(element).nextAll('.errorWrap').removeClass('hideError');
},
unhighlight: function(element) {
$(element).nextAll('.errorWrap').addClass('hideError');
}
});
}
Although I'm sure this could have been done more shorthand, I really like this technique because I didn't have to update any of my pages that contained forms to get it to work. All of the nested divs are dynamically created by javascript, so I can include a global file to any page with forms and it will just work. Thanks for all who offered suggestions.

clone table row

How can i use javascript (i assume) to clone a table row like ive beautifully illustrated in the picture below?
You can hookup a live event to all the buttons. If you give them a class of clone for instance the following will work.
$('input.clone').live('click', function(){
//put jquery this context into a var
var $btn = $(this);
//use .closest() to navigate from the buttno to the closest row and clone it
var $clonedRow = $btn.closest('tr').clone();
//append the cloned row to end of the table
//clean ids if you need to
$clonedRow.find('*').andSelf().filter('[id]').each( function(){
//clear id or change to something else
this.id += '_clone';
});
//finally append new row to end of table
$btn.closest('tbody').append( $clonedRow );
});
Please Note:
If you have elements in the table row with id's you will need to do a .each through them and set them to a new value otherwise you will end up with duplicate id's in the dom which is not valid and can play havoc with jQuery selectors
You can do this like so
If you want a really simple solution, just use innerHTML:
var html = document.getElementById("the row").innerHTML;
var row = document.createElement('p');
row.innerHTML= html;
document.getElementById("table id").appendChild(row);
For what purpose do you want to use the data? I've done similar things previously on data input forms and generally I've found it to be beneficial to the users not to manipulate everything in Javascript but to hook to store the data on the server and interface with AJAX.
The issue is that as soon as you start letting users do this sort of complex table manipulation and they accidentally hit the back button you end up with a lot of disgruntled punters. Coding up transient storage on a database isn't that much harder than manipulating Javascript and in fact can be easier as you can break the operations down more easily. Debugging is simpler for that reason too (you always have inspect access to the current state of your table).
Lots of option for handling via AJAX - the simplest being to just use a place-holder division and feed the whole table structure in as needed.
A jQuery example:
$(document).ready(function(){
$('TABLE.recs').delegate('INPUT.clone','click',function(e){
e.preventDefault();
var s = $(this).parent().parent().clone().wrap('<div>').parent().html();
$('TABLE.recs TBODY TR:last').after(s);
});
});

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