Develop Reference

Click to enlarge image, then click again to make it go back to previous size

I want to be able to click on an image, have it become big, and then when I click it again, make it go back to being small. I'm trying to use an if/else statement to solve this problem, but I still can't figure it out. This is the JS I have so far:
document.addEventListener("DOMContentLoaded", function(event) {
var thumbnailElement = document.getElementById("smart_thumbnail");
if (thumbnailElement.className === "small") {
thumbnailElement.addEventListener("click", function() {
thumbnailElement.className = "";
});
} else {
thumbnailElement.addEventListener("click", function() {
thumbnailElement.className = "small";
});
}
});
And the HTML for the image:
<img class="small" id="smart_thumbnail" src="http://4.bp.blogspot.com/-QFiV4z\
3gloQ/ULd1wyJb1oI/AAAAAAAAEIg/LE1Kakhve9Y/s1600/Hieroglyphs_Ani-papyrus.jpg">
I'm simply wanting to get rid of the "small" class on the id "smart_thumbnail" to make it big and put the "small" class back to make it small again, but I can only make it big. When I click on it the 2nd time, it doesn't do anything. I've tried an if/else if statement and that didn't work. I looked on here for the same question, but could only find stuff about jQuery. Trying to solve this with JavaScript only.
Any help greatly appreciated. Thanks!

The problem is that the code above will only be run once: After loading your site. So only one condition is fullfilled (thumbnailElement.className === "small")
What you want is something along the lines of:
var thumbnailElement = document.getElementById("smart_thumbnail");
thumbnailElement.addEventListener("click", function() {
if (this.className === "small")
this.className = "";
else
this.className = "small";
});
This will check the class when clicking the image.
Alternatively, you can also use classList.toggle

The DOMContentLoaded event only fires once, that is, when the page is loaded. Instead run your if-statement on a per-click basis.
For example
thumbnailElement.addEventListener("click", function() {
if (thumbnailElement.className === "small") {
thumbnailElement.className = "";
} else {
thumbnailElement.className = "small";
}
});
Now you will register the click event once, but every time it is clicked it will check the classname logic and apply the class name appropriately.

js on change event getting looped in js confirm

I have a flip toggle button().I am writing a function on change of toggle button,on change I am declaring js confirm box ,if confirms true the button remains in changed state,else it will revert in its previous state.My issue is the function is getting iterating(looping).Please suggest

To me it looks quite ok. Maybe you just forgot to encapsulate your code in $(document).ready - this is necessary because otherwise your Javascript function will be loaded before the HTML DOM has been loaded - so your function will fail to access the DOM elements.
$(document).ready(function() {
$("#btn").on("change", function() {
var txt;
var btnStatus = $("#btn").val();
console.log("btnstataus>>>>>" + btnStatus);
var r = confirm("Are you sure to change?");
if (r == true) {
if (btnStatus == "on") {
$("#btn").val("on");
} else {
$("#btn").val("off");
}
} else {
if (btnStatus == "on") {
$("#btn").val("off");
} else {
$("#btn").val("on");
}
}
});
});
Here is a working sample of your code:
https://plnkr.co/edit/AdzcN04F1fsLe9xw454j?p=preview

If select input equals value do this, if it is changed remove those changes

I have a select box called "requestHistoryRequestType". I'm trying to write some jQuery so that when the value of that select box is changed I call a function that adds a class and attribute to a field and appends a span to the field that I pass in as a parameter.
The problem is if a user chooses EXPAPP or EXPDEN but then changes their selection to NA it should remove the added stuff from the previous fields and add the same stuff to a different field. Kinda hard to explain, but ask questions away! I'm kinda new to writing complex jQuery like this.
The function that does the adding classes and such:
function requiredField(requiredField) {
$(requiredField).parent().addClass('has-error');
$(requiredField).attr('data-rule-required', true);
$("label[for='" + requiredField.replace('#', '') + "']").append("<span style='color:#b94a48;' class='has-error has-tooltip' data-placement='right' title='Required Field'>*</span>");
}
The actual on change listener:
//Validations for EXPAPP, EXPDEN, and NA
$("#requestHistoryRequestType").on("change", function() {
if ($("#requestHistoryRequestType").val() === "EXPAPP" || $("#requestHistoryRequestType").val() === "EXPDEN"){
requiredField("#requestHistoryVerbalDateTime");
requiredField("#requestHistoryWrittenDateTime");
} else if ($("#requestHistoryRequestType").val() === "NA") {
requiredField("#requestHistoryComments");
}
});
Thanks Stack!

Create a function that would remove the added stuff from all fields and call it before requiredField() calls:
function removeRequiredFields()
{
var $fields = $("#requestHistoryVerbalDateTime, #requestHistoryWrittenDateTime, #requestHistoryComments");
$fields.parent().removeClass('has-error');
$fields.attr('data-rule-required', false);
$fields.each(function() {
$("label[for='"+$(this).attr('id')+"']").find("[title='Required Field']").remove();
});
}
Or you can pass $fields from the event handler to removeRequiredFields() instead of hardcoding it there, for added flexibility.

I would just have a separate function for when you select a "NA" rather then trying to build that functionality into the same function.
I'll rewrite your event handler to make it a bit cleaner as well (IMO).
//Validations for EXPAPP, EXPDEN, and NA
$("#requestHistoryRequestType").on("change", function() {
var selectedVal = $(this).val();
if (selectedVal === "EXPAPP" || selectedVal === "EXPDEN"){
requiredField("#requestHistoryVerbalDateTime");
requiredField("#requestHistoryWrittenDateTime");
} else if (selectedVal === "NA") {
requiredField("#requestHistoryComments");
}
});
This way you are not hitting the DOM a potential 3 time to test your conditions every time an event is triggered. A minor change but probably a useful one as you get into more complex and larger jQuery selectors.
Edit: If you feel you MUST do it in one function then you can call the function with both elements you want to append
function requiredField(requiredField1, requiredField2) {
if (requiredField2 != null){
$(requiredField1,requiredField1).parent().addClass('has-error');
$(requiredField1,requiredField1).attr('data-rule-required', true);
var requiredLabel = "<span style='color:#b94a48;' class='has-error has-tooltip' data-placement='right' title='Required Field'>*</span>"
$("label[for='" + requiredField1.replace('#', '') + "']").append(requiredLabel);
$("label[for='" + requiredField2.replace('#', '') + "']").append(requiredLabel);
}
else {
//remove multiple element classes and add it to the single one representing the "NA"
}
}
This is based on you only ever having one case where you would be passing a single "requiredField" on a case of a "NA"

Disable Select based on another element on the Same Row

In a table, I have a row with two inputs - one select and one text. What I want to achieve is that if one has a value, then the other (on the same row) should disable. This works correctly onload when there is a value in the textbox, but doesn't seem to work when there is a value in only the select box.
As you can see in the example here: http://jsfiddle.net/anAgent/UBUhn/1/ the "change" event works correctly, but it doesn't work onload.
Any help would greatly be appreciated!
I'm working with jQuery 1.5.2 and with both Google Chrome and IE9
Update With Final Code
Thanks #scoopseven and #eicto for your input. Based on these two answers, here's the final code. I hope it helps someone else.
$(document).ready(function() {
$(".validation-compare").change(runRowValidation);
$(".validation-compare").each(runRowValidation);
});
function runRowValidation() {
var $me = $(this),
$other = $('.validation-compare',$me.closest("tr")).not($me),
mVal = $me.val(),
oVal =$other.val();
if(mVal != "" && oVal == "") {
$me.removeAttr('disabled');
$other.attr('disabled',1);
} else if(mVal == "" && oVal != "") {
$other.removeAttr('disabled');
$me.attr('disabled',1);
} else {
$other.removeAttr('disabled');
$me.removeAttr('disabled');
}
}​
You can see it in action at: http://jsfiddle.net/anAgent/UBUhn/24/

i don't think that you you need to set the class valid, all you have to do is replacing
var $otherInput = $('.validation-compare', $parent).not('.valid');
by
var $otherInput = $('.validation-compare', $parent).not($me);
And this will resolve your problem on onload. Here is an example

var validme=function() {
var me=$(this);
me.removeClass('validation-compare');
if (me.val()) {
console.log(me);
me.addClass('valid');
me.parent().parent().find('.validation-compare').attr('disabled',1);
me.addClass('validation-compare');
return;
}
me.removeClass('valid');
if (me.parent().parent().find('.validation-compare.valid').length<1) {
me.parent().parent().find('.validation-compare').removeAttr('disabled'); }
me.addClass('validation-compare');
}
$('.validation-compare').each(validme);
$('.validation-compare').change(validme)
http://jsfiddle.net/UBUhn/22/

You need to separate out the function and call it on the click event and on page load. Something like this:
jQuery(function($){
function myFunction() {
// do somestuff
}
// myFunction needs to be called when select is clicked and when page is loaded
$('#someelement').click(myFunction);
$(document).ready(myFunction);
});

Javascript loop with dynamic jquery val() not being picked up

I'm trying to pick out the value of an input box using jquery.
No probs there
$('#id_of_my_input_box_1').val();
But I need several so decided to put them into a loop:
============
var config_total_instances = '==some value='
for (var x = 1; x <= config_total_instances; x++) {
if (isset($('#id_of_my_input_box_'+x).val())) {
alert($('#id_of_my_input_box_'+x).val());
}
}
============
If I submit the form and I've got say 10 input boxes, the code above doesn't alert a value if the relevant input box has value.
I'm using a function below to check for values.
============
function isset(my_variable) {
if (my_variable == null || my_variable == '' || my_variable == undefined)
return false;
else
return true;
}
============
Am I missing something vital..? :-(
Addition: I shoudl add that I'm askign why I don't get the value of
$('#id_of_my_input_box_'+x).val()
echoed out in my alert box

Extending #Faber75's answer. You can set a class name for all your text element and then use something like this
$("input:text.clsname").each(function(){
if (isset(this.value)) {
alert(this.value);
}
});
In your current code if you are assigning a string to config_total_instances then it will not work.

don't consider my message an answer, more of a tip.
For a simplier code you could consider adding a class to the textboxes you need to check.
For example adding to all the inputs you need to check the class="sample" you could the use the jquery selector $(".sample") , returning you all the items and then you could simply do
$(".sample").length to count the items and $(".sample")[0].val() (or similar) to get/test values.
Cheers

Have you tried this? (note that there are three =)
if (my_variable === null || my_variable == '' || my_variable === undefined)
As an alternative to this try
if (typeof(my_variable) == 'null' || my_variable == '' || typeof(my_variable) == 'undefined')

Maybe I'm misunderstanding, but can't you just get all the <input>'s in a <form> that aren't :empty if that's the end goal of what you're trying to accomplish?
$('form#some_id input:not(:empty)').each(function () {
// do something with $(this).val() now that you have
// all the non-empty <input> boxes?
});
Or if you're just trying to tell if the user left some <input> blank, something like:
$('form#some_id').submit(function (e) {
if ($(this).find('input[type="radio"]:not(:checked), input[type="text"][value=""], select:not(:selected), textarea:empty').length > 0) {
e.preventDefault(); // stops the form from posting, do whatever else you want
}
});
http://api.jquery.com/category/selectors/form-selectors/