show and hide control using javascript based on another dropdown - javascript

I want to hide a control using JavaScript based on the selection of an item in a dropdown list.
Here's what I currently have:
function DDLDGChanged() {
var text = $("#<%= DDLDG.ClientID %> option:selected").text();
alert(text);
if (text == "DG") {
document.getElementById('#<%=DDLPsaGroup.ClientID%>').style.display = "block";
document.getElementById('#<%=Label29.ClientID%>').style.display = "block";
document.getElementById('<%=txtClass.ClientID %>').disabled = false;
}
else {
document.getElementById('#<%=DDLPsaGroup.ClientID%>').style.display = "none";
document.getElementById('#<%=Label29.ClientID%>').style.display = "none";
document.getElementById('<%=txtClass.ClientID %>').disabled = true;
}
}

I am not sure if you can use jQuery, why you are relying on Javascript code. But going by your code, you are mixing both do it either like this:-
Your Way:-
function DDLDGChanged() {
var text = $("#<%= DDLDG.ClientID %> option:selected").text();
alert(text);
if (text == "DG") {
document.getElementById('<%=DDLPsaGroup.ClientID%>').style.display = "block";
document.getElementById('<%=Label29.ClientID%>').style.display = "block";
document.getElementById('<%=txtClass.ClientID %>').disabled = false;
}
else {
document.getElementById('<%=DDLPsaGroup.ClientID%>').style.display = "none";
document.getElementById('<%=Label29.ClientID%>').style.display = "none";
document.getElementById('<%=txtClass.ClientID %>').disabled = true;
}
}
Please note, when you use Javascript method, no need to use # to fetch the control.
Do it with pure jQuery itself, like the way you have retrieved text variable.

Related

Why does my JS 'click event' only run once?

I created a click event that opens a previously 'hidden' div and closes it again once you click the same button.
However, it only runs once (one open and one close) - I'm at a loss to explain why it doesn't work if I click it again.
let readMore = document.getElementById('clickAbout');
let moreInfo = document.getElementById('about');
let changeSepa = document.getElementById('sepChange');
readMore.addEventListener('click', function(){
changeSepa.style.height = '2rem';
if (moreInfo.className == "") {
moreInfo.className = "open";
moreInfo.style.display = 'block';
} else {
moreInfo.style.display = 'none';
}
});
this happens because you're checking if className == "", but you are modifying the className to be "open". On the second click it checks the className which is now "open" and goes to the else block. On the third click you expect for it to go into the first block but the className is still "open".
For an easy fix just change the className in the else block
else {
moreInfo.className = "";
moreInfo.style.display = 'none';
}
Also i suggest you make use of the classList property on elements
https://developer.mozilla.org/en-US/docs/Web/API/Element/classList
using the class list it could look like this:
readMore.addEventListener("click", function () {
changeSepa.style.height = "2rem";
if (moreInfo.className == "") {
moreInfo.classList.add("open");
moreInfo.style.display = "block";
} else {
moreInfo.classList.remove("open");
moreInfo.style.display = "none";
}
});
Or even
readMore.addEventListener("click", function () {
changeSepa.style.height = "2rem";
moreInfo.classList.toggle("open");
if (moreInfo.className == "") {
moreInfo.style.display = "block";
} else {
moreInfo.style.display = "none";
}
});

create a button that shows or hides a div depending on whether it is currently showing

I'm fairly new in with JS and was wondering, if
there is a more cleaner way of writing this code?
I'm trying to create a button that shows or hides a div depending on whether it is currently showing.
Many Thanks in Advance
Anne
var button = document.getElementById('button');
var hideText = document.getElementById('output').className = 'hide';
button.addEventListener('click', ()=>{
if(hideText){
document.getElementById('output').className = 'unhide';
hideText = false;
}else{
document.getElementById('output').className = 'hide';
hideText = true;
}
})
CSS
.hide{display: none;}
.unhide{display: block;}
Just use a single class (e.g. unhide) and make it invisible by default. Then do
button.addEventListener('click', () => {
document.getElementById('output').classList.toggle('unhide');
}
You can just toggle the classes
button.addEventListener('click', () => {
document.getElementById('output').classList.toggle('hide');
}
You can remove the extra variable hideText and also the extra css if you implement like this
var x = document.getElementById("output");
if (x.style.display === "none") {
x.style.display = "block";
} else {
x.style.display = "none";
}
In jquery the are other simpler possible way like toggle, hide, show.

JavaScript doesn't work after I remove one <div> [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 6 years ago.
Improve this question
I am really new to JS and I'm having some issues.
So I have this JS file: that is basically the same function repeating with different <div id="">.
var button = document.getElementById("obj-trigger");
button.onclick = function () {
var div = document.getElementById("obj-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
var button = document.getElementById("lineas-trigger");
button.onclick = function() {
var div = document.getElementById("lineas-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
var button = document.getElementById("cultura-trigger");
button.onclick = function() {
var div = document.getElementById("cultura-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
var button = document.getElementById("igualdad-trigger");
button.onclick = function() {
var div = document.getElementById("igualdad-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
var button = document.getElementById("proyectos-trigger");
button.onclick = function() {
var div = document.getElementById("proyectos-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
var button = document.getElementById("estigmas-trigger");
button.onclick = function() {
var div = document.getElementById("estigmas-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
var button = document.getElementById("soy-trigger");
button.onclick = function() {
var div = document.getElementById("soy-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
var button = document.getElementById("tudef-trigger");
button.onclick = function() {
var div = document.getElementById("tudef-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
And it works perfectly when I am using ALL the functions, however if I remove a <div> from my HTML, let's say: <div id="estigmas-trigger">, my JS will work until it reaches:
var button = document.getElementById("estigmas-trigger");
button.onclick = function() {
var div = document.getElementById("estigmas-cont");
if (div.style.display !== "none") {
div.style.display = "none"
}
else {
div.style.display = "block";
}
};
All code below that will stop working, so no more collapsing. :(
Why is that? And... how can I fix it?
It's because button will be null if there are no element with id estigmas-trigger, and you should get error that you can't set value onclick on null, try adding a check to test if button is not null:
var button = document.getElementById("estigmas-trigger");
if (button) {
button.onclick = function() {
var div = document.getElementById("estigmas-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
}
Your error is caused because when you remove an element from the HTML and then your Javascript tries to refer to that element without proper protections, it causes a script error and the script aborts execution because of the error.
The second thing you need to do when learning Javascript (after learning how to write your first script) is to learn how to check for errors in the debug console in the browser. That will show you when you have execution errors that are aborting your script and they will usually show you what line the error occurs on.
In this case, you would attempt to get a DOM element with a line such as:
var button = document.getElementById("estigmas-trigger");
And, then you would attempt to use the button variable. But, if the estigmas-trigger element was not in the page, then button would be null and it would be an error to reference a property of null such as .onclick.
In addition, your code is horribly repetitive. You really should never copy nearly identical code multiple times into your code. Instead, create a reusable function and use that function multiple places or if your code is almost entirely identical except for one input parameter (which is the case for you), then you can just put the one input parameter into an array and loop through the array.
Here's a much more DRY implementation (this replaces all of your code):
var buttons = ["obj-trigger", "lineas-trigger", "cultura-trigger",
"igualdad-trigger", "proyectos-trigger", "estigmas-trigger",
"soy-trigger", "tudef-trigger"];
buttons.forEach(function(id) {
var button = document.getElementById(id);
if (button) {
button.addEventListener("click", function(e) {
var cont_id = this.id.replace("trigger", "cont");
var elem = document.getElementById(cont_id);
if (elem) {
var style = elem.style;
if (style.display !== "none") {
style.display = "none";
} else {
style.display = "block";
}
}
});
}
});
Summary of changes:
Put all the trigger ID values into an array of strings so you can just loop through each one that you want to apply identical code to.
Use .forEach() to loop through the array of strings.
Get the DOM element for each id and check to see if it is present before trying to use it (this will solve your original problem).
Use .addEventListener() to add the click event handler as this is much more scalable than .onclick because you can have multiple click handlers for the same element this way. It is a generally good habit to switch to use .addEventListener().
Rather than refer to the xxx-cont ids by name, just derive them from the xxx-trigger ids using a simple text replacement. This saves more duplication and typing in your code.
Get the xxx-cont object in the DOM and also check to see if it exists before attempting to use it (safe coding).
One way is:
var button = document.getElementById("estigmas-trigger");
//that way you prevent define a function in a null object
if(button){
button.onclick = function() {
var div = document.getElementById("estigmas-cont");
if (div.style.display !== "none") {
div.style.display = "none";
}
else {
div.style.display = "block";
}
};
}

Javascript show / hide elements

I have a hidden text area (which is defined as hidden with bootstrap)
I have a dropdown which has 2 options.
If I select 1st option, textarea should be shown.
If I select 2nd option, textarea should disappear.
Here are my codes and I don't know where I go wrong :
function OnSelectedIndexChange(){
var getDropDown = document.getElementById("myDropDownID");
var getDropDownSelectedItemValue = getDropDown.options[getDropDown.selectedIndex].text;
if(getDropDownSelectedItemValue == 'Yes'){
document.getElementById("myTextAreaID").style.display = 'block';
}
else{
document.getElementById("myTextAreaID").style.display = 'none';
}
}
UPDATE:
Added jsfiddle link : jsfiddle.net/wy562fk8/1 but i am using blade templating, so you can't be able to see any output.
use onchange function.
document.getElementById("myDropDownID").onchange = function {
if(document.getElementById("myDropDownID").value == 'Yes'){
document.getElementById("myTextAreaID").style.display = 'block';
}
else{
document.getElementById("myTextAreaID").style.display = 'none';
}
}
Might be the reason you are doing
var getDropDownSelectedItemValue = getDropDown.options[getDropDown.selectedIndex].text;
instead of
var getDropDownSelectedItemValue = getDropDown.options[getDropDown.selectedIndex].value;

How do I get the divs to show in javascript?

I have this script on dynamic radio buttons... On load the divs display, great. One is automatically checked, great. If I click the other radio button the divs hide, great. When I click back to the main radio button to show the divs again the divs don't reappear.
How do I get the divs to reappear (show)?????
function hide() {
var ele = document.getElementById("hideRow");
var coup = document.getElementById("coup");
if ("hideRow") {
ele.style.display = "none";
coup.style.display = "none";
} else {
ele.style.display = "block";
coup.style.display = "block";
}
}
Try :
function hide() {
var ele = document.getElementById("hideRow");
var coup = document.getElementById("coup");
if (ele.style.display == "block") {
ele.style.display = "none";
coup.style.display = "none";
} else {
ele.style.display = "block";
coup.style.display = "block";
}
}
This is always true:
if ("hideRow") {
// Always executes
}
So, you only ever get to the if-block. You need to change the conditional on your if-statement.
if (ele.style.visibility == 'visible';) {
ele.style.visibility = 'hidden';
coup.style.visibility = 'hidden';
} else {
ele.style.visibility = 'visible';
coup.style.visibility = 'visible';
}
I may have entirely missed the mark and not understood what your trying to do, but that's the way I'd do it (I think - you may be trying to do something else).

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