I'm trying to find a function in JavaScript that is called everytime when a <form> or <select> is created. Does anyone have a idea?
I want something like:
<body onload="jsFunction();">
More exactly, I need to make a <select> that will be included in many pages, and I want everytime this is loaded, to select one of it's values based on a request variable. So the function that will make the selection must called from this included script and must be included in this script.
I'm using JSP on the server side
This makes no sense. Just set the whole selected attribute programmatically based on the request parameter. Here's an example:
<select name="foo">
<option value="bar" ${param.foo == 'bar' ? 'selected' : ''}>Bar</option>
<option value="baz" ${param.foo == 'baz' ? 'selected' : ''}>Baz</option>
<option value="waa" ${param.foo == 'waa' ? 'selected' : ''}>Waa</option>
</select>
or if you have it in a collection:
<select name="foo">
<c:forEach items="${foos}" var="foo">
<option value="${foo}" ${param.foo == foo ? 'selected' : ''}>${foo}</option>
</c:forEach>
</select>
The same is true for normal inputs:
<input type="text" name="bar" value="${fn:escapeXml(param.bar)}" />
(the fn:escapeXml() is there to prevent XSS attacks)
You could try the "selected" attribute in the option you want to select by default (like suggested here). If you prefer javascript, you'll need to use something like jquery to select select (or populate and select) your tag.
For reference:
<select>
<option>Volvo</option>
<option selected="selected">Saab</option>
<option>Mercedes</option>
<option>Audi</option>
</select>
Related
I know you can use document.forms to check if a radio button or checkbox is checked but I am not sure how you could this for a select since it has multiple options.
This is the code I thought I could use.
JavaScript:
var pick_deliv = document.forms[order]
[pick_deliv].checked;
HTML:
<form>
<select name="pick_deliv" id="pick_deliv">
<option value="pick_up">Pick up </option>
<option value="delivery">Delivery </option>
</select>
</form
Currently I have a dropdown in my edit.blade.php
<div class="md-form">
<select id="estado_civil" name="estado_civil" class="mdb-select validate" onchange="editar('estado_civil',$(this).val());">
<option value=""></option>
<option value="1">Soltero(a)</option>
<option value="2">Unido(a)</option>
<option value="3">Casado(a)</option>
</select>
</div>
I needed the dropdown to select/display the value the user had previously chosen and stored in the database. I achieved this using JQuery:
$(document).ready(function() {
var e = $.Event('change');
$('#estado_civil').val('{{$personas->estado_civil}}').focus().trigger(e);
However, this function registers the display of the pre-selected value as a 'change' upon page load. Therefore, it triggers another function I made that notifies the user the value has changed.
Question: Is there a way to select/display the preselected value from the database, without registering it as a change?
Thank you so much!
I'm not super familiar with Laravel but from a quick read of the docs you'd do something like this in the blade:
<option value="1" {{estado_civil) == 1 ? "selected" : ""}}>Soltero(a)</option>
<option value="2" {{estado_civil) == 2 ? "selected" : ""}}>Unido(a)</option>
This uses a ternary to set the selected value of the input.
I have the following code on another webpage on my site with a form (say on page index.html): JSFiddle
<select class="select form-control" id="dropdown" name="dropdown" onchange="showForm()">
i.e a dropdown form.
I want to have a link on another webpage that will go to this page, and have the "Sales" option already selected.
<option value="1">
Sales
</option>
from the drop down menu (instead of the current default option), how do I create this?
Query parameters can be used to achieve the result you want, but you will need to parse the query parameter manually on your current page, since there is no standard JavaScript method for doing it.
You can write the following code on your page to automatically select the option:
$(document).ready(function() {
// Parse your query parameters here, and assign them to a variable named `queryParams`
var option = queryParams.type;
$("#dropdown").val(option);
});
Now you can create an anchor with the URL of this page, e.g. http://yourpage.url?type=1, which will redirect to this page, and will automatically change the value of your dropdown accordingly.
You must add some kind of router functionality with Javascript in your site.
I think the simplest thing you could do it to have a script in that page that checks the url if it has say a #bar hash like so: http://yoursite.com/foo.html#bar.
<script>
// make sure you run this on DOM ready like in $.ready() in jQuery or in a script just before closing the body tag
if(window.location.hash === 'bar') {
// add the selected attribute to the <option> you want
}
</script>
Try with append() function of jquery .and pass this with in onchange function call .And also added with document.ready for create the link on document load with selected value
function showForm(that){
var s = $(that).children('option:selected').text()
$('#link_box').append(''+s+'</br>')
}
$(document).ready(function(){ // for window load
showForm($('select'))
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="form-group ">
<label class="control-label" for="dropdown">
What can we help you with?
</label>
<select class="select form-control" id="dropdown" name="dropdown" onchange="showForm(this)">
<option value="0" disabled>
Select an option
</option>
<option value="1" selected>
Sales
</option>
<option value="2">
Complaints
</option>
<option value="3">
Queries
</option>
<option value="4">
Ideas
</option>
</select>
</div>
<div id="link_box">
<!-- its a link append box-->
</div>
I have the following piece of code in a contact form for a site I am designing:
<select id="Category" name="Category">
<option value="0" selected="selected" disabled>Category</option>
<option value="1">General Info</option>
<option value="2">Booking</option>
<option value="3">Auditions</option>
</select>
I would like set the menu such that the user cannot leave category as the selected option. Is there any way to do this with HTML? If not, how would I do it with JavaScript?
Thank you
According to the HTML5 spec,
Constraint validation: If the element has its required attribute specified, and either none of the option elements in
the select element's list of options have their
selectedness set to true, or the only option element in
the select element's list of options with its
selectedness set to true is the placeholder label option,
then the element is suffering from being missing.
If a select element has a required attribute
specified, does not have a multiple attribute specified, and
has a display size of 1; and if the value of the first
option element in the select element's list of
options (if any) is the empty string, and that option
element's parent node is the select element (and not an
optgroup element), then that option is the select
element's placeholder label option.
Therefore, you can use
<select id="Category" name="Category" required>
<option value="" selected disabled>Category</option>
<option value="1">General Info</option>
<option value="2">Booking</option>
<option value="3">Auditions</option>
</select>
When the user click on any option, he can´t return the first one back. But he can submit form without change, then you need to validate via JS.
It's quite simple,
function validate() {
var select = document.getElementById('Category');
return !select.value == 0;
}
And the form in HTML:
<form onsubmit="return validate()">...</form>
Will disabling select work for you?
<select id="Category" name="Category" disabled>
<option value="0" selected="selected">Category</option>
...
</select>
Or maybe disabling all but selected option will work for you (as shown here: https://stackoverflow.com/a/23428851/882073)
Ideally, you would simply remove the selected attribute from disabled options on the server side when generating the HTML document to begin with.
Otherwise, if you are using JQuery, this can be done fairly easily with:
$('#Category').find('option:not([disabled])').first().prop('selected', true);
Add this to your ondomready event handler. This will force the first non-disabled option to be selected for this select element regardless of its options' selected attributes. The disadvantage of this method is that it will prevent the selected attribute from being able to be used at all with this select element.
On the other hand, if you are trying to create category headers within a select element, you should consider using an optgroup element instead, since that is the correct semantic markup for this:
<select id="Category" name="Category">
<optgroup label="Category">
<option value="1">General Info</option>
<option value="2">Booking</option>
<option value="3">Auditions</option>
</optgroup>
</select>
How can I check if a user has selected something from a <select> field in HTML?
I see <select> doesn't support the new required attribute... do I have to use JavaScript then? Or is there something I’m missing? :/
Mandatory: Have the first value empty - required works on empty values
Prerequisites: correct html5 DOCTYPE and a named input field
<select name="somename" required>
<option value="">Please select</option>
<option value="one">One</option>
</select>
As per the documentation (the listing and bold is mine)
The required attribute is a boolean
attribute.
When specified, the user
will be required to select a value
before submitting the form.
If a select element
has a required attribute specified,
does not have a multiple attribute specified,
and has a display size of 1 (do not have SIZE=2 or more - omit it if not needed);
and if the value
of the first option element in the
select element's list of options (if
any) is the empty string (i.e. present as value=""),
and that
option element's parent node is the
select element (and not an optgroup
element),
then that option is the
select element's placeholder label
option.
The <select> element does support the required attribute, as per the spec:
http://dev.w3.org/html5/spec-author-view/the-select-element.html#the-select-element
Which browser doesn’t honour this?
(Of course, you have to validate on the server anyway, as you can’t guarantee that users will have JavaScript enabled.)
Yes, it's working:
<select name="somename" required>
<option value="">Please select</option>
<option value="one">One</option>
</select>
you have to keep first option blank.
You can use the selected attribute for the option element to select a choice by default. You can use the required attribute for the select element to ensure that the user selects something.
In Javascript, you can check the selectedIndex property to get the index of the selected option, or you can check the value property to get the value of the selected option.
According to the HTML5 spec, selectedIndex "returns the index of the first selected item, if any, or −1 if there is no selected item. And value "returns the value of the first selected item, if any, or the empty string if there is no selected item." So if selectedIndex = -1, then you know they haven't selected anything.
<button type="button" onclick="displaySelection()">What did I pick?</button>
<script>
function displaySelection()
{
var mySelect = document.getElementById("someSelectElement");
var mySelection = mySelect.selectedIndex;
alert(mySelection);
}
</script>
You need to set the value attribute of option to the empty string:
<select name="status" required>
<option selected disabled value="">what's your status?</option>
<option value="code">coding</option>
<option value="sleep">sleeping</option>
</select>
select will return the value of the selected option to the server when the user presses submit on the form. An empty value is the same as an empty text input -> raising the required message.
w3schools
The value attribute specifies the value to be sent to a server when a form is submitted.
Example
<form action="">
<select required>
<option selected disabled value="">choose</option>
<option value="red">red</option>
<option value="yellow">yellow</option>
<option value="green">green</option>
<option value="grey">grey</option>
</select>
<input type="submit">
</form>
try this, this gonna work, I have tried this and this works.
<!DOCTYPE html>
<html>
<body>
<form action="#">
<select required>
<option value="">None</option>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="mercedes">Mercedes</option>
<option value="audi">Audi</option>
</select>
<input type="submit">
</form>
</body>
</html>
Make the value of first item of selection box to blank.
So when every you post the FORM you get blank value and using this way you would know that user hasn't selected anything from dropdown.
<select name="user_role" required>
<option value="">-Select-</option>
<option value="User">User</option>
<option value="Admin">Admin</option>
</select>
first you have to assign blank value in first option.
i.e. Select here.than only required will work.
Works perfectly fine if the first option's value is null. Explanation : The HTML5 will read a null value on button submit. If not null (value attribute), the selected value is assumed not to be null hence the validation would have worked i.e by checking if there's been data in the option tag. Therefore it will not produce the validation method. However, i guess the other side becomes clear, if the value attribute is set to null ie (value = "" ), HTML5 will detect an empty value on the first or rather the default selected option thus giving out the validation message. Thanks for asking. Happy to help. Glad to know if i did.
In html5 you can do using the full expression:
<select required="required">
I don't know why the short expression doesn't work, but try this one.
It will solve.
Try this
<select>
<option value="" style="display:none">Please select</option>
<option value="one">One</option>
</select>
You can do it also dynamically with JQuery
Set required
$("#select1").attr('required', 'required');
Remove required
$("#select1").removeAttr('required');