How do we implement a cancel in plain Javascript? - javascript

I have a page and I display data in a table.
In each table I have a column with a checkbox which if is checked the user can modify the specific row via Javascript.
This is done as its td encapsulates either an input or a select and I make these editable for the user.
The user modifies the row and presses save and the changes are saved. So far ok.
My problem is how do I implement a cancel?
The user could choose many row i.e. check boxes and modify them but the user could also press cancel. On cancel the original values should be displayed (and the rows become non-editable again).
But how is a cancel operation implemented in Javascript? Do we store data in some global datastructures? Which would be this in Javascript?

Ok, after the addition of informations you provided I suggest you setup the following mecanism:
function getDatas() {
var oXhr;
//get datas from database:
oXhr = new XMLHttpRequest();
oXhr.onreadystatechange = function() {
if (oXhr.readyState == 4 && (oXhr.status == 200)) {
g_oData = (new DOMParser()).parseFromString(oXhr.responseText, "text/xml");
}
}
oXhr.open("POST", "yourphpscriptthatreturnsthexmldatas.php", true);
oXhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded; charset=utf-8");
oXhr.send();
}
function populateGrid() {
//use g_oData to populate your grid, but at first totally clean the body
var mygrid = document.getElementById("mygridid");
//mygrid.innerHtml = "<table><tr><td>...</td></tr></table>";
//use the xml library to parse g_oData and fill up the table:
var xmlRows = g_oData.getElementsByTagName("TAG");
var xmlRow;
iLen = xmlRows.length;
for (var i=0;i<iLen;i++) {
xmlRow = xmlRows[i];
//use xmlRow->textContent to build each cell of your table
}
}
function revertChange() {
//on cancel, revert the changes by populating the grid.
//it will use the global xml/json object loaded directly from database, to refill everything.
populateGrid();
}
I did it myself many times to refresh some datas in a page. That's basically what you're doing except that you're not requesting anything to the database, you just refill the fields.

You can just access the original value attribute of the input to get the defaultValue. Sample implementation:
$("table").on("dblclick", "td", function(e) {
var val = $(this).html();
$(this).empty().append($("<form/>").append(
$("<input/>", {type:"text"}).attr("value", val),
// ^^^^
// set the *attribute*, as if it was present in the parsed HTML
$("<button/>", {type:"reset"}).text("Reset"),
$("<button/>", {type:"button", class:"cancel"}).text("Cancel"),
$("<button/>", {type:"submit"}).text("Submit")
));
}).on("submit", "form", function(e) {
var val = $(this).find("input:text").val();
// ^^^^^
// which is equivalent to .prop("value")
/* then do something with val, e.g. send it to server via ajax */
$(this).parent().html(val);
e.preventDefault();
}).on("click", "button.cancel", function(e) {
var $form = $(this).parent(),
$input = $form.find("input:text"),
oldval = $input.attr("value");
// ^^^^^^^^^^^^^
// or .prop("defaultValue"), but not .val()!
if (oldval == $input.val() || confirm("Do you really want to discard your changes?"))
$(this).parent().html(oldval);
e.preventDefault();
});
(Demo at jsfiddle.net)
A maybe more simple solution might be to use the dblclick-handler that creates the form as a closure and just store the original html in a local variable there.

Here is a pretty simple way:
Don't replace the cell content with the form element. Keep the value (the text) in a span element and hide it when you show the form element. Then you don't have to do anything on cancel. Just show the span again and hide or remove the form element. Only update the span when the user wants to save the value.
Here is an example. The showing and hiding is all done with CSS.
<tr>
<td>
<span>value</span>
<input type='text' value='' />
</td>
<td>
<button class="save">Save</button>
<button class="revert">Revert</button>
</td>
</tr>
JS:
var rows = document.querySelectorAll('table tr');
for(var i = 0, l = rows.length; i < l; i++) {
rows[i].addEventListener('click', function(event) {
// all value display elements in the row
var spans = this.querySelectorAll('span');
// all form elements in the row
var inputs = this.querySelectorAll('input');
// handle click on save button
if (event.target.className === 'save') {
[].forEach.call(inputs, function(input, i) {
spans[i].innerHTML = input.value;
});
this.className = '';
}
// handle click on revert button
else if (event.target.className === 'revert') {
// not much to do
this.className = '';
}
else {
// update form element values
[].forEach.call(inputs, function(input, i) {
input.value = spans[i].innerHTML;
});
this.className = 'edit';
}
});
}
DEMO

You can use the HTML5 data- attributes to implement a revert function. This way, each <input> would hold it's original value in case a revert button would be used.
Here's how it'd look:
<table>
<tr>
<td><input type='text' value='change me' data-original='change me' /></td>
<td><input type='text' value='change me2' data-original='change me2' /></td>
<td><input type='button' value='revert' onclick='revert(this)'/></td>
</tr>
<table>
And the code that reverts:
function revert(btn) {
var parentTr = btn.parentNode.parentNode;
var inputs = parentTr.getElementsByTagName('input');
for(var i = 0; i < inputs.length; i++) {
if (inputs[i].type == 'text') {
inputs[i].value = inputs[i].getAttribute('data-original');
}
}
}
The data-original attribute could be generated:
By the server-side app who serves the page (see (1) demo fiddle here); or
by a JavaScript function that is executed as soon as the DOM is ready (see (2) demo fiddle for this here).
As a side solution, you could store the original values in a map object. Here's the (3) demo for this (notice I added the id for each input, so it can be used as key to the map).
Keep in mind, though, neither solutions (2) or (3) require changing in server side code (the 3 assuming your inputs have ids). And (2) feels clearer.
About the defaultValue attribute: The defaultValue attribute can be a solution only if the value to be reverted never changes and if the fields involved are text inputs.
Firstly, changing the "default value" is rather awkward and may break something else aling the page (one would expect the browsers make the defaultValue attribute read-only, but that does not seem to be the case). Secondly, you would be limited to inputs of the text type.
Still, if none of that is a problem, the code above can be quickly adapted to use them instead of data- attributes.

Related

How to select/Deselect all checkboxes in oracle apex form

I have a page region in Oracle Apex, that contains many checkboxes (apex form).
I want a functionality to add a checkbox at the header of every checkbox item, that will Select/Deselect all the checkbox items underneath.
I am new to Apex development, and need help on this.
Here's a solution that assumes the text above the checkboxes is from the item's label (somehow I don't think that's the case). If needed, I can update the answer to better fit your page when I know more about it.
First, go into each checkbox where you want to add this "toggle" functionality. Scroll down to the CSS Classes attribute and put toggle-cb in the field.
Next, go to the page level attributes and add the following code to the Function and Global Variable Declaration attribute:
function enableToggle() {
var $wrapperDiv = $(this);
var $label = $wrapperDiv.find('.t-Form-label');
var $item = $wrapperDiv.find('.apex-item-checkbox');
var buttonHtml = '<button type="button" class="t-Button t-Button--tiny t-Button--simple">Toggle all</button>';
$label.html($label.text() + ' ' + buttonHtml);
$label.find('button').on('click', function(event) {
var $button = $(this);
var $checkboxes = $item.find('input[type="checkbox"]');
var checkedCount = $checkboxes.filter(function() {
return this.checked === true;
}).length;
var check = checkedCount < $checkboxes.length;
$checkboxes.each(function() {
this.checked = check;
});
event.stopPropagation();
$button.blur();
});
}
Finally, add the following code to the Execute when Page Loads attribute of the page:
$('.toggle-cb').each(enableToggle);
This will add a button to each item's label (provided the checkbox has the toggle-cb class) that does the toggle:
See the following to learn more about the code used above:
https://www.youtube.com/watch?v=Pjur4Zkkwsk&list=PLUo-NIMouZ_sgdQpMbXXwhHKpwRggCY34&index=1

javascript keep values after page reload

I have a general question. I got a form made with django, if i use submit, but not all data is correct or when there are required fields missing, the page jumps back to default.
The values inside the form are saved but not the page lay-out.
my javascript that changes lay-out:
$(function(){
$('li.fields').slice(1).hide();
$('ul').on('click', 'li.title', function(){
$(this).next().slideToggle(200)
})
});
short said, I would like to keep the status of the (un)collapsed fields.
Could someone please point me in the right direction to achieve that (new to javascript)
If you can't use AJAX (or don't know how to use it), you can use a hidden field in your form.
I've created a fiddle to simulate that.
HTML:
<input type="hidden" id="myHiddenField" />
Updated Javascript:
$(function(){
$('li.fields').slice(1).hide();
$('ul').on('click', 'li.title', function(){
$(this).next().slideToggle(200);
var myString = "[ "; // create a string to simulate an Array
$('ul li.title').each(function() {
myString += $(this).is(":visible").toString() + ", "; // iterate your list to take the visible values
});
myString += " ]"; // finishes the Array
$("#myHiddenField").val(myString); // populate your hidden field
})
// when you get back from a submit, this hidden field will have some values
if ($("#myHiddenField").val() != "") {
var arr = eval($("#myHiddenField").val()); // turn the string into an Array
for (var i = 0; i < arr.length; i++) { // iterate the Array
if (!arr[i])
$("ul li.title").eq(i).hide(); // if the Array item is false, hide the respective li
}
}
});

how to get selected radio button from radiobuttonlist in javascript [duplicate]

I have an ASP.NET web page with a databound RadioButtonList. I do not know how many radio buttons will be rendered at design time. I need to determine the SelectedValue on the client via JavaScript. I've tried the following without much luck:
var reasonCode = document.getElementById("RadioButtonList1");
var answer = reasonCode.SelectedValue;
("answer" is being returned as "undefined")
Please forgive my JavaScript ignorance, but what am I doing wrong?
Thanks in advance.
ASP.NET renders a table and a bunch of other mark-up around the actual radio inputs. The following should work:-
var list = document.getElementById("radios"); //Client ID of the radiolist
var inputs = list.getElementsByTagName("input");
var selected;
for (var i = 0; i < inputs.length; i++) {
if (inputs[i].checked) {
selected = inputs[i];
break;
}
}
if (selected) {
alert(selected.value);
}
Try this to get the selected value from the RadioButtonList.
var selectedvalue = $('#<%= yourRadioButtonList.ClientID %> input:checked').val()
I always View Source. You will find each radio button item to have a unique id you can work with and iterate through them to figure out which one is Checked.
Edit: found an example. I have a radio button list rbSearch. This is in an ascx called ReportFilter. In View Source I see
ReportFilter1_rbSearch_0
ReportFilter1_rbSearch_1
ReportFilter1_rbSearch_2
So you can either loop through document.getElementById("ReportFilter1_rbSearch_" + idx ) or have a switch statement, and see which one has .checked = true.
RadioButtonList is an ASP.NET server control. This renders HTML to the browser that includes the radio button you are trying to manipulate using JavaScript.
I'd recommend using something like the IE Developer Toolbar (if you prefer Internet Explorer) or Firebug (if you prefer FireFox) to inspect the HTML output and find the ID of the radio button you want to manipulate in JavaScript.
Then you can use document.getElementByID("radioButtonID").checked from JavaScript to find out whether the radio button is selected or not.
The HTML equivalent to ASP.NET RadioButtonList, is a set of <input type="radio"> with the same name attribute(based on ID property of the RadioButtonList).
You can access this group of radio buttons using getElementsByName.
This is a collection of radio buttons, accessed through their index.
alert( document.getElementsByName('RadioButtonList1') [0].checked );
function CheckRadioListSelectedItem(name) {
var radioButtons = document.getElementsByName(name);
var Cells = radioButtons[0].cells.length;
for (var x = 0; x < Cells; x++) {
if (document.getElementsByName(name + '_' + x)[0].checked) {
return x;
}
}
return -1;
}
For a 'RadioButtonList with only 2 values 'yes' and 'no', I have done this:
var chkval=document.getElemenById("rdnPosition_0")
Here rdnposition_0 refers to the id of the yes ListItem. I got it by viewing the source code of the form.
Then I did chkval.checked to know if the value 'Yes' is checked.
I would like to add the most straightforward solution to this problem:
var reasons= document.getElementsByName("<%=RadioButtonList1.UniqueID%>");
var answer;
for (var j = 0; j < reasons.length; j++) {
if (reason[j].checked) {
answer = reason[j].value;
}
}
UniqueID is the property that gave you the name of the inputs inside the control, so you can just check them really easily.
I've tried various ways of determining a RadioButtonList's SelectedValue in Javascript with no joy. Then I looked at the web page's HTML and realised that ASP.NET renders a RadioButtonList control to a web page as a single-column HTML table!
<table id="rdolst" border="0">
<tr>
<td><input id="rdolst_0" type="radio" name="rdolst" value="Option 1" /><label for="rdolst_0">Option 1</label></td>
</tr>
<tr>
<td><input id="rdolst_1" type="radio" name="rdolst" value="Option 2" /><label for="rdolst_1">Option 2</label></td>
</tr>
</table>
To access an individual ListItem on the RadioButtonList through Javascript, you need to reference it within the cell's child controls (known as nodes in Javascript) on the relevant row. Each ListItem is rendered as the first (zero) element in the first (zero) cell on its row.
This example loops through the RadioButtonList to display the SelectedValue:
var pos, rdolst;
for (pos = 0; pos < rdolst.rows.length; pos++) {
if (rdolst.rows[pos].cells[0].childNodes[0].checked) {
alert(rdolst.rows[pos].cells[0].childNodes[0].value);
//^ Returns value of selected RadioButton
}
}
To select the last item in the RadioButtonList, you would do this:
rdolst.rows[rdolst.rows.length - 1].cells[0].childNodes[0].checked = true;
So interacting with a RadioButtonList in Javascript is very much like working with a regular table. Like I say I've tried most of the other solutions out there but this is the only one which works for me.
I wanted to execute the ShowShouldWait script only if the Page_ClientValidate was true. At the end of the script, the value of b is returned to prevent the postback event in the case it is not valid.
In case anyone is curious, the ShouldShowWait call is used to only show the "please wait" div if the output type selected is "HTML" and not "CSV".
onclientclick="var isGood = Page_ClientValidate('vgTrxByCustomerNumber');if(isGood){ShouldShowWait('optTrxByCustomer');} return isGood"
To check the selected index of drop down in JavaScript:
function SaveQuestion() {
var ddlQues = document.getElementById("<%= ddlQuestion.ClientID %>");
var ddlSubQues = document.getElementById("<%=ddlSecondaryQuestion.ClientID%>");
if (ddlQues.value != "" && ddlSubQues.value != "") {
if (ddlQues.options[ddlQues.selectedIndex].index != 0 ||
ddlSubQues.options[ddlSubQues.selectedIndex].index != 0) {
return true;
} else {
return false;
}
} else {
alert("Please select the Question or Sub Question.");
return false;
}
}
reasonCode.options[reasonCode.selectedIndex].value
From here:
if (RadioButtonList1.SelectedIndex > -1)
{
Label1.Text = "You selected: " + RadioButtonList1.SelectedItem.Text;
}

Dynamic index setting in javascript

I have a table to which i need to add rows dynamically on click of a button. Each row has 3 textboxes and a clear button. On click of clear the data in the textboxes need to be cleared i.e. onclick of the button i send the index of the row to a method which deletes the contents of the textboxes at that index.
Problem - How do i specify the index number in the onClick property of the row button while adding the new row?
How do i specify the index number in the onClick property of the row button while adding the new row?
You don't. Instead, use the fact that the textboxes and the button are in the same row. I probably wouldn't use onclick on the button at all; instead, I'd have a single click handler on the table and handle the button clicks there (this is called event delegation). Something like this:
var table = document.getElementById("theTableID");
table.onclick = function(event) {
var elm, row, boxes, index, box;
// Handle IE difference
event = event || window.event;
// Get the element that was actually clicked (again handling
// IE difference)
elm = event.target || event.srcElement;
// Is it my button?
if (elm.name === "clear") {
// Yes, find the row
while (elm && elm !== table) {
if (elm.tagName.toUpperCase() === "TR") {
// Found it
row = elm;
break;
}
elm = elm.parentNode;
}
if (row) {
// Get all input boxes anywhere in the row
boxes = row.getElementsByTagName("input");
for (index = 0; index < boxes.length; ++index) {
box = boxes[index];
if (box.name === "whatever") {
box.value = "";
}
}
}
}
};
...but if you want to keep using the onclick attribute on the button instead, you can grab the middle of that:
The button:
<input type="button" onclick="clearBoxes(this);" ...>
The function:
function clearBoxes(elm) {
var row, boxes, index, box;
// Find the row
while (elm) {
if (elm.tagName.toUpperCase() === "TR") {
// Found it
row = elm;
break;
}
elm = elm.parentNode;
}
if (row) {
// Get all input boxes anywhere in the row
boxes = row.getElementsByTagName("input");
for (index = 0; index < boxes.length; ++index) {
box = boxes[index];
if (box.name === "whatever") {
box.value = "";
}
}
}
}
References:
DOM2 Core specification - well-supported by all major browsers
DOM2 HTML specification - bindings between the DOM and HTML
DOM3 Core specification - some updates, not all supported by all major browsers
HTML5 specification - which now has the DOM/HTML bindings in it, such as for HTMLInputElement so you know about the value and name properties.
Off-topic: As you can see, I've had to work around some browser differences and do some simple utility things (like finding the nearest parent element of an element) explicitly in that code. If you use a decent JavaScript library like jQuery, Prototype, YUI, Closure, or any of several others, they'll do those things for you, letting you concentrate on your actual problem.
To give you an idea, here's that first example (handling the click via event delegation) written with jQuery:
$("#theTableID").delegate("input:button[name='clear']", "click", function() {
$(this).closest("tr").find("input:text[name='whatever']").val("");
});
Yes, really. And other libraries will similarly make things simpler.
Best to use event delegation, or you can use this in JavaScript.
Event Delegation w/jQuery
<input class="clear-row-btn" type="button" >Clear Row</input>
.live event
$(".clear-row-btn").live("click", function(){
var $tr = $(this).closest("tr");
$tr.find("input[type='text']").val("");
});
HTML w/onclick method
<input type="button" onclick="clearRow(this)" >Clear Row</input>
jQuery
function clearRow(btn) {
var $tr = $(btn).closest("tr");
$tr.find("input[type='text']").val("");
}
JavaScript
function clearRow(element) {
while(element.nodeName!='TR'){
element = element.parentNode;
}
//find textboxes inside the element, which is now the parent <tr>
}

Limit the number of children in a form using Javascript

I am trying to limit the number of additional form input fields that a user can add dynamically to a file upload form to just 3. The form is loaded with one static input field and through javascript can add additional fields with an add button or remove additional form input fields with a remove button. Below is the html in it's static form.
<fieldset>
<legend>Upload your images</legend>
<ol id="add_images">
<li>
<input type="file" class="input" name="files[]" />
</li>
</ol>
<input type="button" name="addFile" id="addFile" value="Add Another Image" onclick="window.addFile(this);"/>
</fieldset>
With javascript I would like to create a function where the number of child elements are counted and if the number is equal to three then the "Add Another Image" button becomes disabled. In addition, if there are three elements in the form the user - with the remove button - removes a child then the "Add Another Image" button becomes enabled again.
I think I'm may be missing some crucial lines of code. The below javascript code only allows me to add one additional input field before the Add Another Image button becomes disabled. Removing this field with the remove file button removes the field but the Add Another Image button is still disabled. Below is where I'm currently at with the javascript.
function addFile(addFileButton) {
var form = document.getElementById('add_images');
var li = form.appendChild(document.createElement("li"));
//add additional input fields should the user want to upload additional images.
var f = li.appendChild(document.createElement("input"));
f.className="input";
f.type="file";
f.name="files[]";
//add a remove field button should the user want to remove a file
var rb = li.appendChild(document.createElement("input"));
rb.type="button";
rb.value="Remove File";
rb.onclick = function () {
form.removeChild(this.parentNode);
}
//create the option to dispable the addFileButton if the child nodes total "3"
var nodelist;
var count;
nodelist = form.childNodes;
count = nodelist.length;
for(i = 0; i < count; i++) {
if (nodelist[i] ==3) {
document.getElementById("addFile").disabled = 'true';
}
else { //if there are less than three keep the button enabled
document.getElementById("addFile").disabled = 'false';
}
}
}
Oh, OK, I've tested out the code now and see a couple of problems:
You're counting the number of child elements but this includes the text elements so there's actually one for the <li> and one for the text within it.
You've enclosed the true/false setting for the disabled property in quotes but it doesn't work and always set's it to false.
The remove button doesn't re-enable the add button.
I found this to work:
function addFile(addFileButton) {
var form = document.getElementById('add_images');
var li = form.appendChild(document.createElement("li"));
//add additional input fields should the user want to upload additional images.
var f = li.appendChild(document.createElement("input"));
f.className="input";
f.type="file";
f.name="files[]";
//add a remove field button should the user want to remove a file
var rb = li.appendChild(document.createElement("input"));
rb.type="button";
rb.value="Remove File";
rb.onclick = function () {
form.removeChild(this.parentNode);
toggleButton();
}
toggleButton();
}
function toggleButton() {
var form = document.getElementById('add_images');
//create the option to dispable the addFileButton if the child nodes total "3"
var nodelist;
var count;
nodelist = form.childNodes;
count = 0;
for(i = 0; i < nodelist.length; i++) {
if(nodelist[i].nodeType == 1) {
count++;
}
}
if (count >= 3) {
document.getElementById("addFile").disabled = true;
}
else { //if there are less than three keep the button enabled
document.getElementById("addFile").disabled = false;
}
}
I would suggest a slightly different approach. Create all three file input fields statically and provide a clear button. If the user chooses to leave it empty they can. If that is not elegant use your "Remove" to simply hide the field (CSS style display: none;).
I'm not sure why you're using the for loop? Shouldn't it be like this:
var nodelist = form.childNodes;
if (nodelist.length >= 3) {
document.getElementById("addFile").disabled = 'true';
}
else { //if there are less than three keep the button enabled
document.getElementById("addFile").disabled = 'false';
}
The last part of that function is a bit strange. Technically, when adding fields, you should only be disabling the button (i.e. you could never enable the button by adding fields). I would suggest removing the for loop and going with:
var count = form.getElementsByTagName("li").length;
if(count == 3)
document.getElementById("addFile").disabled = true;
The reason the add field button is still disabled when you remove an item is because you don't re-enable the add field button when you click remove. Try this for the remove button click handler:
rb.onclick = function () {
form.removeChild(this.parentNode);
document.getElementById("addFile").disabled = false;
}

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