How implement subj?
when i write:
<form>
<select>
<option value="0">aaaa</option>
<option value="1">bbbb</option>
</select>
</form>
then default selected item is "aaaa"
when i write:
<form>
<select>
<option value=""></option>
<option value="0">aaaa</option>
<option value="1">bbbb</option>
</select>
</form>
then default selected item is blank, but this blank item presents in drop down.
how i can implement SELECT tag with default blank value that hidden in dropdown list?
Just use disabled and/or hidden attributes:
<option selected disabled hidden style='display: none' value=''></option>
selected makes this option the default one.
disabled makes this option unclickable.
style='display: none' makes this option not displayed in older browsers. See: Can I Use documentation for hidden attribute.
hidden makes this option to don't be displayed in the drop-down list.
You can by setting selectedIndex to -1 using .prop: http://jsfiddle.net/R9auG/.
For older jQuery versions use .attr instead of .prop: http://jsfiddle.net/R9auG/71/.
Simply using
<option value="" selected disabled>Please select an option...</option>
will work anywhere without script and allow you to instruct the user at the same time.
<select>
<option value="" style="display:none;"></option>
<option value="0">aaaa</option>
<option value="1">bbbb</option>
</select>
Here is a simple way to do it using plain JavaScript. This is the vanilla equivalent of the jQuery script posted by pimvdb. You can test it here.
<script type='text/javascript'>
window.onload = function(){
document.getElementById('id_here').selectedIndex = -1;
}
</script>
.
<select id="id_here">
<option>aaaa</option>
<option>bbbb</option>
</select>
Make sure the "id_here" matches in the form and in the JavaScript.
You can't. They simply do not work that way. A drop down menu must have one of its options selected at all times.
You could (although I don't recommend it) watch for a change event and then use JS to delete the first option if it is blank.
For purely html #isherwood has a great solution. For jQuery, give your select drop down an ID then select it with jQuery:
<form>
<select id="myDropDown">
<option value="0">aaaa</option>
<option value="1">bbbb</option>
</select>
</form>
Then use this jQuery to clear the drop down on page load:
$(document).ready(function() {
$('#myDropDown').val('');
});
Or put it inside a function by itself:
$('#myDropDown').val('');
accomplishes what you're looking for and it is easy to put this in functions that may get called on your page if you need to blank out the drop down without reloading the page.
You can try this snippet
$("#your-id")[0].selectedIndex = -1
It worked for me.
Related
I'm looking for a way to set a default value (in a select list) that has to be switched out of in order for the 'required=""' attribute to be accepted and for the form to be submitted. In other words the default value can't stay as the chosen value. Also, how would one add titles to a select list that can not be chosen and are meant as a way of labeling the select options. Everything I am looking for is shown in the image below in case of confusion.
In other words the default value can't stay as the chosen value.
About this request, you could find this helpful.
<form action="/action_page.php">
<select id="mySelect" required onchange="changeValue()">
<option value="">Select a Country</option>
<option value="c1">Country 1</option>
<option selected value="c2">Country 2</option>
<option value="c3">Country 3</option>
<option value="c4">COuntry 4</option>
</select>
<input id="btnSubmit" type="submit" disabled>
</form>
<script>
function changeValue(){
if (document.getElementById("mySelect").value != "")
document.getElementById("btnSubmit").disabled = false;
}
</script>
If your selected value changes (just after the first time) and it's different from "", the submit button will be valid. This can also be accomplished with a flag instead of setting the property disable, it depends on what you need to do.
You could try checking with javascript if the value = ""
Example from w3Schools.com:
https://www.w3schools.com/js/js_validation.asp
Make sure you also validate on the server side! people could change the HTML / Javascript
With input of type text the attribute required is available. It is not the case for select inputs. So how to make them required ?
FIDDLE
<form>
<select required>
<option></option><!--If this is selected require pop up will appear -->
<option>test</option><!--If this is selected form will be submitted -->
</select>
<input type="submit">
</form>
You can make them required by using html5 attribute required just like below.
<select required>
<option value="">select an option</option>
<option value="value1">Value 1</option>
<option value="value2">Value 2</option>
</select>
View Example in jsfiddle http://jsfiddle.net/88rXX/
Set a default value then on form submission check to see if that default value has changed.
If you're using the JQuery validation plug-in, try this Validate select box
You do have to remember though that just because it's validated client side, doesn't mean you shouldn't also check server side.
use it based on html 5. otherwise you can use any plugin
How exactly can I go about making a select tag readonly. I've read that you can't set a select as readonly. I do that I can set it as disabled but... That is not an option. I would like the user to view the rest of the options in the select tag, but not be able to pick one of them..
Any ideas?
you can use disabled attribute.
for example.
<select >
<option disabled="disabled" value="volvo">Volvo</option>
<option disabled="disabled" value="saab">Saab</option>
<option disabled="disabled" value="mercedes">Mercedes</option>
<option disabled="disabled" value="audi">Audi</option>
</select>
assume that tag id="mySelectID", and jQuery is resident, then :
<script language="javascript">
// disable all the options that are not in use:
$("#mySelectID option").not(":selected").attr("disabled", "disabled");
// to remove readonly, enable them again:
$("#mySelectID option").not(":selected").attr("disabled", "");
</script>
You can make it fake-readonly by adding style="pointer-events:none;"
I used the selected disabled values for the option tag.
It will serve the purpose of prompting the user to select an option and at the same time disabling that option.
Example:
<option selected disabled>-Select-</option>
https://coderanch.com/t/469173/select-box-READONLY-true
if you want to disable the select box, then you can use a javascript code to enable it back before the form submits. So on the onsubmit event of the form, you can enable the select box so that its value is also submitted when the form is submitted...
Does native HTML have a listbox element? You know how it has a drop box element (called select), does it also have a listbox?
If not, do you know how I could place a list box in my Website.
One method, is to create a table & have each element detect the onclick event. But I dont want to make my own just yet. Are javascript widgets easy to use?
Use a select list:
<select multiple="multiple" size="2">
<option value="Whatever">One</option>
<option value="Other">Two</option>
</select>
#Myles has the select box which is correct, you can also allow multiple select options.
<select multiple="multiple">
<option value="opt1">Option 1</option>
<option value="opt2">Option 2</option>
<option value="opt3">Option 3</option>
</select>
Add the multiple attribute to a normal <select> and use the size attribute to determine how many rows you want shown. (If you don't set the size attribute, then all options will be visible.):
<select multiple="multiple" size="5">
See example.
I think what you need is the select tag, but set the selects attributes of multiple and size. Here is a reference http://www.w3schools.com/tags/tag_select.asp.
<select multiple='multiple' size='3'>
<option value='o1'>Red</option>
<option value='o2'>Green</option>
<option value='o3'>Blue</option>
</select>
At this moment the standards do not have a listbox element.
There's a web spec in progress about the <selectmenu> element which does have a listbox slot (not element). Possibly this could end up being back in the <select> element
If you want to read more about it:
https://open-ui.org/prototypes/selectmenu
https://css-tricks.com/the-selectmenu-element/
Is there any way I can trap html select events, and prevent the html select dropdown to open? (Disabling html select is ruled out since the events will be disabled too.)
I doubt this will actually prevent it from opening, but it will ensure that the DropDown will always maintain the same value:
<select name="theselect" onchange="this.selectedIndex = 1;">
<option value="Red">Red</option>
<option value="Green" selected="selected">Green</option>
<option value="Blue">Blue</option>
</select>
This doesn't disable the "dropdown to open", but if you don't want anything selectable, a trick I used was to make <optgroup> instead of option. However, I'm confused why you would want to disable the dropdown, but disabling it is not option...
If you don't want to drop down a drop down box then why make it a drop down control.
Use an image that looks like a drop down and set it as the background if you need to get the feel of a drop down box.
I second what Myles says: You hope you find these links useful:
Making custom dropdowns
http://jonathan.tang.name/code/jquery_combobox
Demo:
http://jonathan.tang.name/files/jquery_combobox/demo.html
You could remove all of the options from the dropdown, or hide the current select element and replace it with an empty one.
<select id="main">
<option name="1">1</option>
<option name="2">2</option>
<option name="3">3</option>
</select>
<select id="empty" style="display:none;">
</select>
<script>
function disableSelect() {
document.getElementById('main').style.display = 'none';
document.getElementById('main').style.display = '';
}
</style>