How to specify each option at a select tag?,using which attribute (name,id,....)?
and how to recieve it in the server script to detect which option is selected?
Here's a standard select box, in which value and content are different:
<select name="color_id">
<option value="1">Red</option>
<option value="2">Blue</option>
<option value="3">Green</option>
</select>
Upon form submission, $_GET['color_id'] or $_POST['color_id'] (depending on the form method) would be set to 2 if the user had selected Blue.
If the content of the option is the value you want to send, no need to repeat yourself; the option's value is set to the content if no other value is specified.
<select name="color_id">
<option>Red</option>
<option>Blue</option>
<option>Green</option>
</select>
Upon form submission, $_GET['color_id'] or $_POST['color_id'] (depending on the form method) would be set to Blue if the user had selected Blue.
The index in $_GET or $_POST will be the name of the select tag. The contents of the array element will be the value of the option.
You use this:
<select name="select1">
<option value="val1">Option 1</option>
<option value="val2">Option 2</option>
</select>
As for the server side, it depends on which technology you are using.
edit sorry I didn't see you tagged it as php. $_POST or $_GET will contain the "select1" item, depending on which method you're using in your form tag.
Related
I am doing PHP validation, and I was reading w3.org on forms. Can anyone clarify this statement
"When no options are selected, the control is not successful and neither the name nor any values are submitted to the server when the form is submitted". To test this, I have created
<form method="get" action="#">
<select name="select_name" >
<option value="">Select one</option>
<option value="one">Choice one</option>
<option value="two" >Choice two</option>
<option value="three">Choice three</option>
</select>
</form>
When I print the GET array, I see that the name "select_name" always passed to the server. For radio and checkbox, this is not true. But I do not understand what that statement trying to say. Is it possible for "neither name nor value" to be passed during select option?
The specification you quoted:
When no options are selected, the control is not successful and neither the name nor any values are submitted to the server when the form is submitted.
...indicates what to do when no options are selected, but by default most browsers will automatically select the first option of a (drop-down) select element. Do you not see on your test page that the first option "Select one" is automatically selected when the page loads? In your case where the first option has an empty string as its value if you then submitted the form with that option selected you should have a request parameter with the name "select_name" and a value that is an empty string.
In the case of a (non-drop-down) select multiple element:
<select name="select_name" multiple>
...no option is selected by default so then if you submit without selecting any options you should see that you don't get a "select_name" request parameter.
NOTE: You tagged your question with "PHP", but this is not a PHP thing. It's the browser that forms the request according to the state of the form controls at the time.
So I have a select feild with various options, the default is an option prompting the user to select from the drop down with a value of "empty". If the user declines to change the drop down before submission, rather than sending a string containing "empty" the form changes the feild to the top option within the select and sends that data instead. My code is included below:
<select class="num" name="Team_1">
<option value="empty" class="red">Please Select</option>
<option value="1">Manchester United</option>
<option value="2">Bristol City</option>
<option value="4">Spurs</option>
<option value="9">Testing</option>
</select>
If you submit the above form with the Please select option chosen, it reverts ti Manchester United and sends a string containing "1"
Any ideas why it might be doing this and/or how i can stop it?
You always should identify which option should be selected by default.
<option value="empty" class="red" selected="selected">Please Select</option>
Change the value of each option tag to that string you want to be send once the form is submitted.
After further investigation I have found the option does not support the class attribute and so by adding class="red" to the option it invalidates the html which then prevents the data from being submitted and so it reverts to the next available value.
My form contains a radio-button & a drop-down. So depending upon the selected value of radio button i need to enable/disable the drop-down.
I am doing this:
<select name="bas_type" id="bas_type" disabled="disabled">
<option value="Monthly">Monthly</option>
<option value="Quarterly">Quarterly</option>
<option value="Annualy">Annualy</option>
</select>
But i want to get drop-down value as empty in $_POST if form is disabled..
So this won't work. Please any suggestions..
Simply add a hidden field with the value you want to receive when the control is disabled and the same name as the dropdown. Be sure to place it before the dropdown in the HTML:
<input type="hidden" name="bas_type" value="" />
<select name="bas_type" id="bas_type" disabled="disabled">
<option value="Monthly">Monthly</option>
<option value="Quarterly">Quarterly</option>
<option value="Annualy">Annualy</option>
</select>
Of course you shouldn't really have to do this, since in PHP you should be receiving incoming parameters with at least a helper function like
function param($name, $default = null) {
return isset($_REQUEST[$name]) ? $_REQUEST[$name] : $default;
}
Don't rely on data you get from form. What you should actually do is check serverside if radiobutton is active or not, and depending on that ignore or accept value from dropbox.
Set the value in the form to "" and that should do the trick:
<option value="">Annualy</option>
or use a space like this (not sure which will work better for you, haven't tried to do it):
<option value=" ">Annualy</option>
Edit: The data contained in the value="something" is the actual data that is passed to the URL via a get. Hence, if you blank it out, the data won't get passed.
I've 2 select boxes with same id's as well as names but at a time only one is shown.
But when form is posted i do not get the exact value.It only displays the first value from the dropdown.
Following is a sample code of the same.
<?php
var_dump($_POST)
?>
<form method="POST" action="">
<select name="test" id="test">
<option value="0">0</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<select name="test" id="test" style="display:none" >
<option value="0">0</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<input type="submit" value="Add"/>
</form>
I even tried surrounding the select box with a div and then hidding it.
Not sure why you have two select's with the same name, but when you hide one you also need to disable it too (disabled="disabled").
As per HTML specification, disabled fields are not submitted so you should have your true value posted from the select that isn't disabled.
Presumably you're using some javascript to switch which select is displayed?
If that's the case, then start off with
<select name="test" id="test"></select>
<select name="test_dummy" id="test_dummy" style="display:none" ></select>
And whichever code changes the style attribute will also have to change the name and id attributes
Even when one of these is hidden at every point, they should have different names in the markup so you can identify which one is which.
Otherwise it'll pass only the last element's (in the markup) value through the form (no matter if it's hidden via CSS or not).
I'm not quite sure why your hiding/showing only one of these at a time anyway. It'd likely be better if you replaced the <option>'s inside the select to the new ones, instead of using show/hide.
You would have to have different id's and in your code conditionally check which select box value is visible fetch it's value.
When you submit a form, the POST data contains data basing on the attribute name. If they have the same name, the value of the second select overwrites the value chosen from the first one. Even if you hide it in the page.
If you want to have just the value of the first select, you should disable the second one, by adding disabled="disabled" or by changing its name.
Need help on this problem.
I have a form being displayed on let's say index.php containing many different fields i.e. drop-down, textfields,...
On the same page, I have a drop-down list containing values coming from my database.
I need to fill in the form based on the value selected from the drop-down list.
Is there a solution for this problem using ajax or even any other way of doing it?
Thanks in advance?
you have to use javascript/ajax. You can use jQuery for this.
You need something like this:
<script type='text/javascript'>
function changeOptions(value,objId){
respond = sendRequestToAPHPScript(); // respond is a string that your php script returns; should contain html for the select box.
${objId}.innerHTML = respond;
}
</script>
<select id="mySelect" onchange="changeOptions(this.value,'mySelect2');">
<option value="1">Option 1</option>
<option value="2">Option 2</option>
</select>
<select id="mySelect2">
<option value="1">Option 1</option>
<option value="2">Option 2</option>
</select>
When you change the dropdown value of the first dropdown a javascript function (changeOptions) is called. The function sends a request to your php script, which outputs html with data from your database. The function then fills the other select box with returned html from the request.
You could listen for changes in the selected dropdown field and make an ajax request to a script that queries the database and returns the desired information in JSON. You'd then have to apply the values to the specified input fields.
Update:
You'll have to figure out the ajax part yourself, but this should get you started. The sample is built using the jquery library.
http://jsfiddle.net/k4emic/4qAE2/2/