javascript function to remove null value - javascript

am trying to remove null value in listbox so first i tried with loop and then one guy helped to do this way but its not removing a null value and empty space...can some body
help out this problem by javascript..
<script type="text/javascript">
function change()
{
//document.getElementById("Geography").options[7]=new Option("", "newval", true, false);
var optionsArr = [];
optionsArr.push(document.getElementById("Geography").options);
optionsArr.push(document.getElementById("zone").options);
optionsArr.push(document.getElementById("country").options);
var optArrlenght = optionsArr.length;
for ( var j = 0; j < optArrlenght; j++){
var options = optionsArr[j];
var optionslength = options.length
for (var i = 0; i < optionslength; i++)
{
if (options[i].innerHTML == "Null Value" || options[i].innerHTML == "")
{
options.removeChild(options[i]);
// OR
// options.options[i] = null;
}
}
}
}
</script>
</head>
<body onload="change()">
Geography:<select id="Geography">
<option value="0"></option>
<option value="1">Null Value</option>
<option value="2">item 2</option>
<option value="3">item 3</option>
<option value="4">item 4</option>
<option value="0">All</option>
</select>
zone: <select id="zone" >
<option value="0"></option>
<option value="1">Null Value</option>
<option value="2">item 2</option>
<option value="3">item 3</option>
<option value="4">item 4</option>
<option value="0">All</option>
</select>
country:<select id="country" >
<option value="0"></option>
<option value="1">Null Value</option>
<option value="2">item 2</option>
<option value="3">item 3</option>
<option value="4">item 4</option>
<option value="0">All</option>
</select>
</body>

Hi whether u have found out solution or not still i put my answer here..
http://jsbin.com/awUWAMeN/2/edit
function change()
{
$('select').each(function() {
$(this).find('option:contains("Null Value")').remove();
});
}

This is not the proper way to remove a dom element: .removeChild() should be called on the elements parent. Instead of options.removeChild(options[i]);, try:
options[i].parentElement.removeChild(options[i]);
Also, if you want to remove the element from the array options call the following:
options.splice(i, 1);

You just need to make the following changes:
1.
<option value="0"></option>
<option value="Null Value">Null Value</option>
<option value="item 2">item 2</option>
<option value="item 3">item 3</option>
<option value="item 4">item 4</option>
<option value="All">All</option>
2.Inside Loop in function change you need to do following
if (options[i].value == "Null Value" )
{ options.removeChild(options[i]);}
if(options[i].innerHTML == "")
{ options.removeChild(options[i])}

Related

How to pass values without using onChange() in HTML but in JavaScript?

I know this is a simple question. But I couldn't find a way to overcome this issue. All I want is this. I have a drop-down created using select element & when user selecting a city from that drop-down it should be able to pass that selected value to console ( console.log() ). But I am able to pass very first selected value only. I found a way to pass values to console using onChange() with select element as following code.
HTML
<select id="comboA" onchange="getComboA(this)">
<option value="">Select combo</option>
<option value="Value1">Text1</option>
<option value="Value2">Text2</option>
<option value="Value3">Text3</option>
</select>
JS
function getComboA(selectObject) {
var value = selectObject.value;
console.log(value);
}
But in my case, the whole procedure needs to be code without using onChange() in HTML. Because I have to get user inputs from WordPress form and need to make separate JS file from the form. So, I can't add or change HTML code of the form. My code is below.
HTML code
<select name="city" class="city" id="city-selection">
<option selected="selected" value="">Select City</option>
<option value="City 1">City 1</option>
<option value="City 2">City 2</option>
<option value="City 3">City 3</option>
<option value="City 4">City 4</option>
<option value="City 5">City 5</option>
<option value="City 6">City 6</option>
<option value="City 7">City 7</option>
</select>
The JS code I used is below.
JS code
var cityVal = document.getElementById("city-selection");
var cityCon = cityVal.options[cityVal.selectedIndex].text;
console.log(cityCon);
Please help me with this issue.
const selectElement = document.querySelector('#city-selection');
const changeHandler = (ev) => {
console.log('Change!', ev.target.value);
}
selectElement.addEventListener('change', changeHandler);
<select name="city" class="city" id="city-selection">
<option selected="selected" value="">Select City</option>
<option value="City 1">City 1</option>
<option value="City 2">City 2</option>
<option value="City 3">City 3</option>
<option value="City 4">City 4</option>
<option value="City 5">City 5</option>
<option value="City 6">City 6</option>
<option value="City 7">City 7</option>
</select>
Please take a look on this fiddle:
Fiddle
const selectCites = document.getElementById("city-selection");
selectCites.addEventListener("change", function(e) {
e.preventDefault();
const { srcElement } = e;
const { selectedOptions } = srcElement;
for (let i = 0; i < selectedOptions.length; i++) {
console.log(selectedOptions[i].value);
console.log(selectedOptions[i].text);
}
})
Basically I added a event listener on the select and wait for any changes and then I loop through the selectedOptions in a case you have more than one.
Just add the EventListener to listen for a change-event:
document.addEventListener("change", function() {
var cityVal = document.getElementById("city-selection");
var cityCon = cityVal.options[cityVal.selectedIndex].text;
console.log(cityCon);
}
You can register an external event listener to respond to the change event like this:
document.querySelector('select[name="city"]').addEventListener('change',function(e){
console.log( 'value: %s - Text: %s',this.value, this.options[ this.options.selectedIndex ].text )
});
<select name="city" class="city" id="city-selection">
<option selected="selected" value="">Select City</option>
<option value="City 1">City 1</option>
<option value="City 2">City 2</option>
<option value="City 3">City 3</option>
<option value="City 4">City 4</option>
<option value="City 5">City 5</option>
<option value="City 6">City 6</option>
<option value="City 7">City 7</option>
</select>
you cant use target property. like this :
const myCombo = document.getELementByID("myCombo");
myCombo.addEventListener("change" , (e) => {
console.log(e.target.value)
});
Almost all the best alternatives has been given, you can either use pure javascript or jquery
Say this is your HTML codes for Cities in Tanzania:
<select name="city" class="city" id="city-selection">
<option selected="selected" value="">Select City</option>
<option value="dar">Dar es Salaam </option>
<option value="mbeya">Mbeya</option>
<option value="mwanza">Mwanza</option>
<option value="dodoma">Dodoma</option>
<option value="arusha">Arusha</option>
<option value="morogoro">Morogoro</option>
<option value="tanga">Tanga</option>
<option value="zanzibar">Zanzibar City</option>
<option value="kigoma">Kigoma</option>
</select>
So your pure javascript can be:
document.getElementById('city-selection').addEventListener('change', function() {
let selectedCity = this.value;
console.log(selectedCity);
});
Jquery:
$('#city-selection').on('change', function() {
let selectedCity = $(this).val();
//let selectedCity = this.value; this will also do the same
//as the above declaration format
console.log(selectedCity);
});
I hope this can be of help to you

Disable certain options in a drop down select

Need to disable option "5" & "6" when the option value "2" is selected. It should display all the options in the List_2 when option "1" is selected. How can I do that using jQuery or any other method.
if ($('option[value=2]').prop('selected', true)) {
$('option[value=5]').prop('disabled', true);
}
<HTML>
<body>
<select id= "List_1">
<option value="1">Option 1</option>
<option value="2">Option 2</option>
</select>
<select id= "List_2">
<option value="4">Option 4</option>
<option value="5">Option 5</option>
<option value="6">Option 6</option>
</select>
</body>
</HTML>
Here you go with a solution https://jsfiddle.net/eurbvzk1/
var disabledDic = {
"1" : ["6"],
"2" : ["4", "5"],
"3" : []
}
$('select#list_1').on('change', function(){
$('select#list_2 option').each(function(){
$(this).removeAttr('disabled');
});
var disableOption = disabledDic[$(this).val()];
$.each( disableOption, function(i){
$('option[value="' + disableOption[i] + '"]').prop('disabled', 'disabled');
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select id="list_1">
<option value="1">Option 1</option>
<option value="2">Option 2</option>
<option value="3">Option 2</option>
</select>
<select id= "list_2">
<option value="4">Option 4</option>
<option value="5">Option 5</option>
<option value="6">Option 6</option>
</select>
Create a dictionary that will contain each first select option as key & value will be list of disabled options from second list.
Onchange method check the dictionary & loop through the disabled value.
Hope this will help you.
With plain JS:
document.getElementById('List_1').onchange = function() {
document.getElementById('List_2')[1].disabled = (document.getElementById('List_1').selectedIndex == 1);
document.getElementById('List_2')[2].disabled = (document.getElementById('List_1').selectedIndex == 1);
}
<select id="List_1">
<option value="1">Option 1</option>
<option value="2">Option 2</option>
</select>
<select id="List_2">
<option value="4">Option 4</option>
<option value="5">Option 5</option>
<option value="6">Option 6</option>
</select>

Hiding the currently selected option

I am surrently having an issue using JQuery. I have 2 select fields.
<select id="cat" name="cat_id">
<option value="2">Cat 2</option>
<option value="3">Cat 3</option>
<option value="4">Cat 4</option>
</select>
<select id="subcat" name="subcat_id">
<option class="subcats cat_2" value="1">Subcat 1</option>
<option class="subcats cat_2" value="2">Subcat 2</option>
<option class="subcats cat_3" value="3">Subcat 3</option>
<option class="subcats cat_3" value="4">Subcat 4</option>
<option class="subcats cat_3" value="5">Subcat 5</option>
<option class="subcats cat_0" value="0">No subcats for this cat</option>
</select>
And here is my JavaScript code
<script type="text/javascript">
var curval = $("#cat").val();
$(".subcats").hide(0);
$(".cat_"+curval).show(0);
$("#cat").change(function(){
var cat = $(this).val();
$(".subcats").removeAttr("selected").hide(0);
if($(".cat_"+cat).length == 0){$(".cat_0").show(0);}
else{$(".cat_"+cat).show(0);}
});
</script>
Here is the problem. When I change the value of the cats select, the options for the subcats are changed correctly. However, the currently selected field is still showing (Even if it doesn't correspond to the current cat).
Any help would be greatly appreciated.
You should change your code a little bit so on the hange event it can add the selected attribute to the first element in the available options :)
var curval = $("#cat").val();
$(".subcats").hide(0);
$(".cat_" + curval).show(0);
$("#cat").change(function() {
var cat = $(this).val();
$(".subcats").removeAttr("selected").hide(0);
if ($(".cat_" + cat).length == 0) {
$(".cat_0").attr("selected", "selected").show(0);
} else {
$(".cat_" + cat).eq(0).attr("selected", "selected");
$(".cat_" + cat).show(0);
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<select id="cat" name="cat_id">
<option value="2">Cat 2</option>
<option value="3">Cat 3</option>
<option value="4">Cat 4</option>
</select>
<select id="subcat" name="subcat_id">
<option class="subcats cat_2" value="1">Subcat 1</option>
<option class="subcats cat_2" value="2">Subcat 2</option>
<option class="subcats cat_3" value="3">Subcat 3</option>
<option class="subcats cat_3" value="4">Subcat 4</option>
<option class="subcats cat_3" value="5">Subcat 5</option>
<option class="subcats cat_0" value="0">No subcats for this cat</option>
</select>

Getting a value from a list

I have a list like that:
<select size="1">
<option value="1">Option 1</option>
<option value="2">Option 2</option>
<option value="3">Option 3</option>
<option value="4">Option 4</option>
<option value="5">Option 5</option>
</select>
How can I get the value of this options with JavaScript (Getting the "1", "2", "3" and so on...).
if you add the id of "list" to <select> this should work: Example Here
document.getElementById('list').onchange = function( e) {
alert( this.value )
}
to get it directly without using this:
document.getElementById('list').value
document.getElementsByTagName("select")[0].value;
or
mySelection = function(element){
console.log(element.value);
}
<select onchange="mySelection(this);">

Javascript works only in firefox

Can anyone please why does this javascript work only in firefox?
function filter(obj, what, where)
{
var v = obj.value;
var d = document.getElementById(where).getElementsByTagName('optgroup');
if (v > 0)
{
for (var i = 0; l = d.length, i < l; i++)
{
d[i].className = 'hide';
if (d[i].id == what + '_' + v)
d[i].className = '';
}
}
else
{
for (var i = 0; l = d.length, i < l; i++)
d[i].className = '';
}
}
I tested it in opera, IE7 and chrome but it doesn't work! Opera error console doesn't show any javascript errors when the page is loaded!
This javascript creates three level auto populating drop down boxes...
I don't know whether it's necessary or not but I post the HTML code too...
State:
<select name="state" onchange="filter(this, 'state', 'district');">
<option value="0"></option>
<option value="1">State 1</option>
<option value="2">State 2</option>
<option value="3">State 3</option>
</select>
District:
<select name="district" id="district" onchange="filter(this, 'district', 'city');">
<option value="0"></option>
<optgroup id="state_1" label="State 1">
<option value="1">District 1</option>
<option value="2">District 2</option>
</optgroup>
<optgroup id="state_2" label="State 2">
<option value="3">District 3</option>
</optgroup>
<optgroup id="state_3" label="State 3">
<option value="4">District 4</option>
<option value="5">District 5</option>
<option value="6">District 6</option>
</optgroup>
</select>
City:
<select name="city" id="city">
<option value="0"></option>
<optgroup id="district_1" label="District 1">
<option value="1">City 1</option>
<option value="2">City 2</option>
<option value="3">City 3</option>
</optgroup>
<optgroup id="district_2" label="District 2">
<option value="4">City 4</option>
<option value="5">City 5</option>
</optgroup>
<optgroup id="district_3" label="District 3">
<option value="6">City 6</option>
<option value="7">City 7</option>
</optgroup>
</select>
ok I know whats happening. It works. IE and possibly other browsers don't support many css properties on <optgroup>. I'm assuming you have something like this:
optgroup.hide {display:none;}
The above works in firefox but doesn't in IE. I used firebug lite to see that IE indeed applied the 'hide' class to the optgroup. I then tried changing the background to red instead of display:none and it works in IE. I think you have to find another way of hiding the optgroup. Maybe remove it from the select altogether and add it back in afterwards.
See my sample code below.
<!doctype html>
<html>
<head>
<title></title>
<style type="text/css">
.hide{background:red}
</style>
<script type="text/javascript">
function filterSelect(obj, what, elID)
{
alert(elID);
var v = obj.value;
var d = document.getElementById(elID).getElementsByTagName('optgroup');
if (v > 0)
{
for (var i = 0; l = d.length, i < l; i++)
{
d[i].className = 'hide';
if (d[i].id == what + '_' + v)
d[i].className = '';
}
}
else
{
for (var i = 0; l = d.length, i < l; i++)
d[i].className = '';
}
}
</script>
</head>
<body>
State:
<select name="state" onchange="filterSelect(this, 'state', 'district');">
<option value="0"></option>
<option value="1">State 1</option>
<option value="2">State 2</option>
<option value="3">State 3</option>
</select>
District:
<select name="district" id="district" onchange="filterSelect(this, 'district', 'city');">
<option value="0"></option>
<optgroup id="state_1" label="State 1">
<option value="1">District 1</option>
<option value="2">District 2</option>
</optgroup>
<optgroup id="state_2" label="State 2">
<option value="3">District 3</option>
</optgroup>
<optgroup id="state_3" label="State 3">
<option value="4">District 4</option>
<option value="5">District 5</option>
<option value="6">District 6</option>
</optgroup>
</select>
City:
<select name="city" id="city">
<option value="0"></option>
<optgroup id="district_1" label="District 1">
<option value="1">City 1</option>
<option value="2">City 2</option>
<option value="3">City 3</option>
</optgroup>
<optgroup id="district_2" label="District 2">
<option value="4">City 4</option>
<option value="5">City 5</option>
</optgroup>
<optgroup id="district_3" label="District 3">
<option value="6">City 6</option>
<option value="7">City 7</option>
</optgroup>
</select>
</body>
</html>

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