Dynamically loading select boxes on page load - javascript

I'm dynamically populating several select boxes via ajax calls when my app first opens. When the page loads however, what I am noticing is my select boxes start out empty and then once populated they adjust their size accordingly. This is annoying and a bit of a UI distraction.
I do have the population methods within my document.ready method, but perhaps I am approaching this incorrectly?
$(document).ready( function(){
populateOptions(); // Populate our select box upon page load.
});
// Builds a select list and binds it to a class
function populateOptions(){
var optionList = getOptions();
var myList = "";
// Loop over our returned result set and build our options
for(i=0; optionList.length; i++){
myList += "<option>"+optionList[i][1]+"</option>";
}
// Now take our myList and append it to our select
$("#myOptionList").append(myList);
}
Options: <select id="myOptionList"></select>

you can set a width to the select by css

Add a dummy option to show while Loading via AJAX:
<select id="myOptionList">
<option>Loading...</option>
</select>
Clear "loading" option and add new list once available
$("#myOptionList").html('');
$("#myOptionList").append(myList);
to set width with css:
#myOptionList{
width:150px;
}

One simple solution would be to create your child directly when your ajax function is called.
Before finishing your populateOptions() function, append the select to your .
I remember having this issue, it is possible to solve it but this is a very simple way to handle it.
Hope this help.

Related

Create a function to hide divs

I want to display tables when a selection is made in a form and a 'Generate Factsheet' button is clicked. I've got a working code where I individually hide other divs when displaying the one I am interested in. Since I have several options in the form (and hence several corresponding divs in which the respective tables are enclosed), the final code appears bulky. I want to write a function to hide other divs whiles displaying the one I am interested in. This is the code I currently have:
var tableDivs = ['tableOPVDiv','tablePneumoDiv','tableRotaDiv'];
var selectedVaccine;
var selectedTableDiv;
function generateFactsheetFunction(){
// Selecting the vaccine chosen from the dropdown
var e = document.getElementById("selectVaccine");
selectedVaccine = e.options[e.selectedIndex].text;
console.log("selectedVaccine: ", selectedVaccine);
if (selectedVaccine=="Rotavirus Vaccine"){
selectedTableDiv='tableRotaDiv';
console.log("rotavirus selected");
hideOtherTables();
} else if (selectedVaccine=="Polio Vaccine"){
console.log("polio selected");
selectedTableDiv='tableOPVDiv';
hideOtherTables();
} else if (selectedVaccine=="Pneumococcal Vaccine"){
console.log("pneumo selected");
selectedTableDiv='tablePneumoDiv';
hideOtherTables();
}
}
function hideOtherTables(){
var testa = tableDivs.indexOf(selectedTableDiv);
console.log("tableDivs[testa]: ", tableDivs[testa]);
console.log("testa: ", testa);
testb = tableDivs[testa];
console.log("testb: ", testb);
document.getElementById(tableDivs[testa]).style.display="block";
/*var newTableDivs=tableDivs.splice(testa);*/
/*for (y=0;y<newTableDivs.length;y++){
document.getElementById(newTableDivs[y]).style.display="none";
}*/
}
The uncommented part works fine. In the commented part, I want to say that for all array elements other than selectedVaccine, I want the display to be:
document.getElementById(tableDivs[testa]).style.display="none";
I cannot splice the data because the selections are repititive (the selections are from a form). What is the way to set the visibility of tableDivs associated with other selections to be none.
Why should you change the display property of each and every division seperately? give a common class name to all the divisions and hide them all at once and then display only the required table.
$(".yourClass").hide();
document.getElementById(tableDivs[testa]).style.display="block";
You will have to use the jQuery Library too.
If you are not familiar with jQuery then use the for loop to hide all the tables first and then display only the required table.
for (y=0;y<TableDivs.length;y++){//you need not create newTableDivs
document.getElementById(TableDivs[y]).style.display="none";
}
document.getElementById(tableDivs[testa]).style.display="block";
i.e you just have to interchange the order of execution. ;)
Cannot read property 'style' of null this means that document.getElementById(tableDivs[y]) return null and can not find this element
try to write
document.getElementById("ElementId")

jQuery: Put dynamically generated input values to span/div

I'm trying to create form for printing with dynamically generated inputs.
Contents of the fields is shown later in PreviewDiv.
It works fine as long as I specify where they should be, for example:
$('#Prw_CapacityA_1').text($('#CapacityA_1').val());
$('#Prw_CapacityB_1').text($('#CapacityB_1').val());
$('#Prw_CapacityC_1').text($('#CapacityC_1').val());
But if the user creates 100 fields this would be a lot of code to write.
There must be other methods to fix this dynamically, for example:
$('#Prw_CapacityA_'+ counter).text($('#CapacityA_'+ counter).val());
Here's the js fiddle
You could try using attribute starts with selector to select the elements starting with the specific id's and then loop through them using the each() function.
There is no need to have html within your preview table. You can generate it when the user clicks on preview. Modified fiddle
$('#PreviewButton').click(function(){
var capB = $('td input[id^=CapacityB_]');
var capC = $('td input[id^=CapacityC_]');
var table = $("#AddFieldsToPreviewDiv");
table.empty(); //build table everytime user previews so that previously appended values are removed
table.append('<tr><td>ID</td><td>Text 1</td><td>Text 2</td><td>Text 3</td></tr>');
$('td input[id^=CapacityA_]').each(function(i){
table.append('<tr><td>#'+(i + 1)
+'</td><td>'+$(this).val()
+'</td><td>'+$(capB[i]).val()
+'</td><td>'+$(capC[i]).val()
+'</td></tr>');
});
// Show PreviewDiv and hide FormDiv if PreviewButton clicked
$('#PreviewDiv').show();
$('#FormDiv').hide();
});
You could try giving them a unique class (Normally I'd suggest ID but you're using one) say a class of "getinfo"
You could then try the .each() function
https://api.jquery.com/each/
$( ".getinfo" ).each(function( index ) {
var text = $(this).val();
alert(text);
});
This will make an alert box for every element it finds with the class 'getinfo' and then retrieve the value and display it, I hope this gives you a better idea.
If the amount of inputs can change from one page load to the next then you need to use a loop, rather than pulling all the values by 'hand', More code will help better understand what you're trying to achieve and from what.

Unable to select first element from select using Jquery

I am filling a drop down based on the value selected in the first drop down.Data being sent back from server is in JSON format and using JQuery to parse and fill the second select tag
<select name="abc" id="jobName">
<option value="-1">Please select a Job</option>
</select>
This is my Jquery code
var selectedGroup = document.getElementById(groupDropDownId);
var groupdata = selectedGroup.options[selectedGroup.selectedIndex].value;
var formInput='group='+groupdata;
$.getJSON('search/getSchedulerJobListForGroup',formInput,function(data) {
$('.result').html('' + data.jobList + '');
$.each(data.jobList,function(index, value){
var jobId = document.getElementById(resetDropDownId);
var option=new Option(value,value);
try{
jobId.add(option);
}
catch(e){
jobId.appendChild(option);
}
});
});
$("#jobName")[0].selectedIndex = 1;
// $("#jobName").val($("#triggerjobName option:first").val());
in above code groupDropDownId is ID of the drop down based on whose value, second drop down will be filled.resetDropDownId is ID of second drop down which i am trying to fill from JSON data getting from the server.
Upon filling the drop down, its also creating an empty option tag and it is getting select by default.
I am not sure if i can add some default value to that empty option so that i can select that default option value like "please select bla bla."
also i tried to select first element from the drop down but nothing seems working for me.I am wondering what i am doing wrong here?
Based on your question, it looks like you want to know how to change the value and text of an element within a dynamically populated select list.
Currently, you have this statement $("#jobName")[0].selectedIndex = 1; sitting outside of your getJSON request. If you move this inside of the getJSON function, it will work as expected.
If you want to set the value and text of that object, you'll want to use ->
$('#jobId option:first').val("Some Value").text("other stuff");
You can see a working JS Fiddle using dynamically populated select list from a JSON object.
Fiddle

How to get values from dynamically added (using javascript) elements?

On my aspx page I dynamically create html controls on client side using javascript. For example, after page load you can click button in a browser, by clicking button html input and select elements appear. You may click once again, and this elements (input and select) will added again. So, you can create so many inputs and selects as you want (all this using javascript, no postbacks)
After user created some inputs and selects and entered some information in it, he posted form. I want on server side to find all this dynamically added elements and perform some actions depends on values in this controls.
How can I find dynamically added elements, and what is the best and elegant way to achieve this?
Thanks in advance.
In the Javascript that creates the new elements, increment a counter each time an element is created. Add the value of the counter to the name of the input element so each element has a unique name.
Add the final value of the counter to a hidden form field when the form is posted.
In your server side code, create a loop that starts at zero and continues until you have reached the value of the counter. Within the loop, fetch the posted value of the corresponding form field.
When you add the elements, assign unique IDs to them, and then retrieve their values using Request.Form["UniqueIdHere"] (C#) or Request.Form("UniqueIdHere") (VB.NET).
Create a loop that loops through each input and select object, that grabs the name/id of the current object and its corresponding value. Then add those items to an array and once the loop is completed, pass those values to your aspx file.
You can view an example with this approach at: http://jsfiddle.net/euHeX/. It currently just alerts the values, but you could easily modify it to pass the values as a parameter via ajax to your handler aspx file. The code will add new inputs or select boxes based off of the input provided. This would of course be modified to reflect your current setup.
HTML:
<div id="dynamic"></div>
<input type="button" id="submit-form" value="Submit>>">
JavaScript (using jQuery):
function createInput(type){
for(var i=0; i<5; i++){
if(type==0){
var obj = '<input type="text" id="'+i+'" class="dynamicContent">';
}else if(type==1){
var obj = '<select id="'+i+'" class="dynamicContent"><option>--Select--</option></select>';
}
$("#dynamic").append(obj);
}
}
function getContent(){
var inputArray = [];
$(".dynamicContent").each(function(k,v){
var o = $(this);
var oType;
if(o.is("input")){ oType = "input"; }
if(o.is("select")){ oType = "select"; }
var oID = oType+o.attr("id");
var oValue = o.val();
inputArray.push(oID+'='+oValue);
});
alert(inputArray);
}
$("#submit-form").click(function(){
getContent();
});
// Set type to 0 for input or 1 for select
var type = '1';
createInput(type);
If you're using jQuery you can use .live() to achive this like a peace of cake!
http://api.jquery.com/live/
I don't know if your controls will survive the postback the way you're creating them, but a good technique for accessing dynamically generated controls (assuming that you've figured out how to persist them) is to do something like the following:
Add a panel to your page. Add your dynamically created controls to this panel.
In the OnClick event handler (or other method), do something like the following:
foreach (DropDownList ddl in Panel1.Controls.OfType<DropDownList>())
{
//put code here
}
foreach (TextBox txt in Panel1.Controls.OfType<TextBox>())
{
//put code here
}

Dynamically generate the content of Drop Down list via jQuery

I am new to Javascript, JSON and jQuery. So please be easy on me. I have a JSP page that contain a drop down list. The contents of the drop down list are populated when the page is loaded. I wrote a Servlet that return the contain of the drop down list in the form of Map, and convert it to JSON string and sent back to the jsp via response.getWriter().write(json); However I am having trouble to getting the result back from the jsp side, and populate the contain of the drop down list from the result. Here are my codes
customer.jsp
$(document).ready(function() {
getCustomerOption('customer'); //try to pre-populate the customer drop down list
});
function getCustomerOption(ddId) {
var dd = $('#' + ddId);
$.getJSON("http://localhost:8080/WebApps/DDListJASON", function(opts) {
$('>option', dd).remove(); // Remove all the previous option of the drop down
if (opts) {
$.each(opts, function(key, value) {
dd.append($('<option/>').val(key).text(value));
}
}
});
}
down where the drop down list is generated
<select id="customer" name="customer">
<option></option>
</select>
The result is nothing get populated into the list. So sad
I think you are invoking the wrong function in document ready
Shouldn't it be
getInitialOption('customer');
instead of
getCustomerOption('customer');
You may add additional <option> elements to a <select> with the code:
$("#selectID").append("<option>" + text + "</option>");
see: JQuery Docs
I don't understand $(''), but I'm not sure that's the problem either, hard to tell exactly.
I do know it will be quicker if you do create the list of options in-memory and then do one append with .html(options) rather than append them one at a time. That may make it easier to understand also, to build the html up one line at a time and then append it.

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