Develop Reference

how to validate userinput with javascript

I have this scenario where i have 4 drop down boxes, where you can choose CM for a carport and a shed, within that carport.
I want to prompt the user with messages/errors in these scenarios:
the shed is chosen to be wider than it is long.
the shed is atleast 60cm smaller than the carports in both width and length
only one of the sheds dimensions being chosen
the form looks like this
<form name="createorder" action="FrontController" method="POST">
<input type="hidden" name="command" value="createorder">
<br>
Length of shed:<br>
<select name="lengthShed">
<option value="0">I do not want a shed</option>
<option value="180">180cm</option>
<option value="210">210cm</option>
<option value="240">240cm</option>
<option value="270">270cm</option>
<option value="300">300cm</option>
<option value="330">330cm</option>
<option value="360">360cm</option>
<option value="390">390cm</option>
<option value="420">420cm</option>
<option value="450">450cm</option>
<option value="480">480cm</option>
<option value="510">510cm</option>
<option value="540">540cm</option>
<option value="570">570cm</option>
<option value="600">600cm</option>
<option value="630">630cm</option>
<option value="660">660cm</option>
<option value="690">690cm</option>
<option value="720">720cm</option>
</select>
<br>
Width of shed:<br>
<select name="widthShed">
<option value="0">I do not want a shed</option>
<option value="18=">180cm</option>
<option value="210">210cm</option>
<option value="240">240cm</option>
<option value="270">270cm</option>
<option value="300">300cm</option>
<option value="330">330cm</option>
<option value="360">360cm</option>
<option value="390">390cm</option>
<option value="420">420cm</option>
<option value="450">450cm</option>
<option value="480">480cm</option>
<option value="510">510cm</option>
<option value="540">540cm</option>
<option value="570">570cm</option>
<option value="600">600cm</option>
<option value="630">630cm</option>
<option value="660">660cm</option>
<option value="690">690cm</option>
</select>
<br>
Width:<br>
<select name="width">
<option value="240">240cm</option>
<option value="270">270cm</option>
<option value="300">300cm</option>
<option value="330">330cm</option>
<option value="360">360cm</option>
<option value="390">390cm</option>
<option value="420">420cm</option>
<option value="450">450cm</option>
<option value="480">480cm</option>
<option value="510">510cm</option>
<option value="540">540cm</option>
<option value="570">570cm</option>
<option value="600">600cm</option>
<option value="630">630cm</option>
<option value="660">660cm</option>
<option value="690">690cm</option>
<option value="720">720cm</option>
<option value="750">750cm</option>
</select>
<br>
Length:<br>
<select name="length">
<option value="240">240cm</option>
<option value="270">270cm</option>
<option value="300">300cm</option>
<option value="330">330cm</option>
<option value="360">360cm</option>
<option value="390">390cm</option>
<option value="420">420cm</option>
<option value="450">450cm</option>
<option value="480">480cm</option>
<option value="510">510cm</option>
<option value="540">540cm</option>
<option value="570">570cm</option>
<option value="600">600cm</option>
<option value="630">630cm</option>
<option value="660">660cm</option>
<option value="690">690cm</option>
<option value="720">720cm</option>
<option value="750">750cm</option>
<option value="780">780cm</option>
</select>

Bind a function to your <select> elements onchange property.
let selects = document.querySelectorAll('select');
for(var i = 0; i < selects.length; i++){
selects[i].onchange = function(){
// Check for your conditions
// If your warning conditions are met, prompt user
}
}
That is, assuming you want the validation to happen when the user changes one of the select's values.
If you want to validate with a button click, you can instead bind the function to the click event of the button.
let button = document.getElementById(buttonID);
button.onclick = function(){
// Check for your conditions
// If conditions are met, prompt user
}
To prompt the user, you can use a simple alert() to which you pass your message. Or make a more elaborate function to do something custom.
As for your conditions, that sounds like commercial math. Might have to split your question in multiple questions here as there are a lot of possible awnsers.
It might be easier for you to add IDs to your selects so you can get them via document.getElementById(idString). You can then get their value through document.getElementById(idString).value. And to use it in math solving, you will need to parse the string that the <select> will return as value, like so parseInt(document.getelementById(idString).value).

Scroll down to selected option on button click using jquery

I have a list of countries like this:
The list is very extensive. I need to be able on a button click to move (focus) to the specified country.
There are many threads in StackOverflow but none of them worked. For example I tried this:
var code = 40;
$('#id_resource-regions').val(code).scrollTop(160);
There is no response and no error/warnings in the developers tool.
Note that the list is created using django forms and templates.

Select the option element you are looking for.
Get the offset top position using .offset(), of the selected option element.
Get the offset top of the select element.
Use .scrollTop() to scroll to the desired option.
Here is an example
var btn = $('button')
var select = $('select')
btn.on('click', function() {
var option = select.find("option:contains('item-30')");
var optionTop = option.offset().top
var selectTop = select.offset().top;
select.scrollTop(select.scrollTop() + (optionTop - selectTop));
option.prop('selected', true)
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select name="" id="select" multiple="multiple">
<option value="">item-1</option>
<option value="">item-2</option>
<option value="">item-3</option>
<option value="">item-4</option>
<option value="">item-5</option>
<option value="">item-6</option>
<option value="">item-7</option>
<option value="">item-8</option>
<option value="">item-9</option>
<option value="">item-10</option>
<option value="">item-11</option>
<option value="">item-12</option>
<option value="">item-13</option>
<option value="">item-14</option>
<option value="">item-15</option>
<option value="">item-16</option>
<option value="">item-17</option>
<option value="">item-18</option>
<option value="">item-19</option>
<option value="">item-20</option>
<option value="">item-21</option>
<option value="">item-22</option>
<option value="">item-23</option>
<option value="">item-24</option>
<option value="">item-25</option>
<option value="">item-26</option>
<option value="">item-27</option>
<option value="">item-28</option>
<option value="">item-29</option>
<option value="">item-30</option>
<option value="">item-31</option>
<option value="">item-32</option>
<option value="">item-33</option>
<option value="">item-34</option>
<option value="">item-35</option>
<option value="">item-36</option>
<option value="">item-37</option>
<option value="">item-38</option>
<option value="">item-39</option>
<option value="">item-40</option>
</select>
<button>move to item 30</button>

Jquery Multi select - How to collapse a opt group

I am using the Jquery multi select tool located here http://www.erichynds.com/blog/jquery-ui-multiselect-widget and I got everything working great. I have a very long list of items and divded by optgroups. You have to scroll quite a lot of get to the last item so im wondering if theres a way to collapse the opt group by default?
I looked at documentation regarding this script but didn't see any functions to collapse by optgroup.
<select name="selSea" id="selSeaShells" size="5" multiple="multiple" onchange="loopSelected()">
<optgroup label="Group 1"/>
<option value="test">test</option>
<option value="test1">test1</option>
<option value="test2">test2</option>
<option value="test3">test3</option>
<optgroup label="Group2"/>
<option value="test">test</option>
<option value="test1">test1</option>
<option value="test2">test2</option>
<option value="test3">test3</option>
<option value="test4">test4</option>
<optgroup label="Group3"/>
<option value="test">test</option>
<option value="test1">test1</option>
<option value="test2">test2</option>
<option value="test3">test3</option>
<option value="test4">test4</option>
</select>

You may try Select2. Also, you may refer to this Stackoverflow discussion.
Using Select2:
In your CSS, hide the sub results by default:
.select2-result-sub > li.select2-result {
display: none;
}
Then add this to your Javascript file:
$('.select2-results').on('click', 'li', function(){
$(this).find('li').show();
});

jQuery Multiple Star Rating system using Select Option dropdown

I found this simple jQuery Star rating system that I'd like to use, I am following http://jsfiddle.net/ code in my website and it's working fine for one star rating system not for multiple and I have multiple star rating system on one page in my website.
Here is jsfiddle link: http://jsfiddle.net/IrvinDominin/eeG86/
<select name="my_input" id="rating_simple">
<option value="0" selected="selected">---Select---</option>
<option value="1">Poor</option>
<option value="2">Below Average</option>
<option value="3">Average</option>
<option value="4">Good</option>
<option value="5">Excellent</option>
</select>
<select name="my_input" id="rating_simple">
<option value="0" selected="selected">---Select---</option>
<option value="1">Poor</option>
<option value="2">Below Average</option>
<option value="3">Average</option>
<option value="4">Good</option>
<option value="5">Excellent</option>
</select>
<select name="my_input" id="rating_simple">
<option value="0" selected="selected">---Select---</option>
<option value="1">Poor</option>
<option value="2">Below Average</option>
<option value="3">Average</option>
<option value="4">Good</option>
<option value="5">Excellent</option>
</select>
In above link I had like jQuery drop down but this is working only for one rating system on one page. My problem is I have multiple star rating system on one page.

Your first problem is the fact that you're using IDs, let's alter your markup for each select to use a class:
<select name="my_input" class="rating_simple">
Now we need to update your jQuery to reflect the change (using . instead of #).
Finally, in your change method, you refer to the star rating system using $(".webwidget_rating_simple"), but now we have multiple of these in the DOM, so we need to refer to the one adjacent to the current select that you're changing, using $(this).next(".webwidget_rating_simple").
So finally, your jQuery will look like this:
EDIT we actually need to setup each dropdown individually, this is to prevent the issue within the plugin that will select all dropdowns if you click on one star (it's better to alter the calling code than it is to update the plugin).
$(".rating_simple").each(function () {
$(this).webwidget_rating_simple({
rating_star_length: '5',
rating_initial_value: '',
rating_function_name: ''
});
});
$('.rating_simple').change(function () {
$(this).next(".webwidget_rating_simple").children("li").css('background-image', 'url(http://www.jhwebdesigner.com/rating-system/rating-system//nst.gif)');
$(this).next(".webwidget_rating_simple").children("li").slice(0,this.value).css('background-image', 'url(http://www.jhwebdesigner.com/rating-system/rating-system//sth.gif)');
});
DEMO

Try this. use different id and name.
<select name="my_input1" id="rating_simple1">
<option value="0" selected="selected">---Select---</option>
<option value="1">Poor</option>
<option value="2">Below Average</option>
<option value="3">Average</option>
<option value="4">Good</option>
<option value="5">Excellent</option>
</select>
<select name="my_input2" id="rating_simple2">
<option value="0" selected="selected">---Select---</option>
<option value="1">Poor</option>
<option value="2">Below Average</option>
<option value="3">Average</option>
<option value="4">Good</option>
<option value="5">Excellent</option>
</select>
<select name="my_input2" id="rating_simple2">
<option value="0" selected="selected">---Select---</option>
<option value="1">Poor</option>
<option value="2">Below Average</option>
<option value="3">Average</option>
<option value="4">Good</option>
<option value="5">Excellent</option>
</select>

Dynamically creating complex select objects in a web form

I am designing a webform that may capture anywhere from 1 to 150 rows of data giving definitions to what type of data is provided in a given row of a csv. These rows of data are all exactly same but I do not know how many of them will be used at the outset. I would like to start with one row and let the end user click an add button to add a new row. On the W-3 schools website there was a small tutorial on how to do this:
http://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_select_create
but there are some problems I am seeing. first, it is buggy. If you go to the link and click the 'try it' button it will create a simple select dropdown. Wonderful! However, If you click it again it then creates a blank one, with every subsequent click creating the same. The other problem is that the select element I would need to use is huge (160 possible options) and uses optgroups to keep it separated and intuitive here is a sample:
<select name="data_value" id="data_value_selector">
<optgroup label="Entity Provider">
<option style="margin-left:12px;" value="name">Name</option>
<option style="margin-left:12px;" value="dba">DBA</option>
<option style="margin-left:12px;" value="facility_type">Facility Type</option>
</optgroup>
<optgroup label="Individual Provider"></optgroup>
<optgroup style="margin-left:12px;" label="Name">
<option value="full_name">Full Name</option>
<option value="name_prefix">Prefix</option>
<option value="first_name">First Name</option>
<option value="middle_name">Middle Name</option>
<option value="last_name">Last Name</option>
<option value="name_suffix">Suffix</option>
<option value="pro_suffix">Professional Suffix</option>
</optgroup>
<optgroup style="margin-left:12px;" label="Birth Date">
<option value="full_birth_date">Full Birth Date</option>
<option value="day_of_birth">Day Of Birth</option>
<option value="month_of_birth">Month Of Birth</option>
<option value="year_of_birth">Year Of Birth</option>
</optgroup>
<optgroup style="margin-left:12px;" label="Education">
<option value="education_institution">Education Institution</option>
<option value="education_city">Education City</option>
<option value="education_county">Education County</option>
<option value="education_state">Education State</option>
<option value="education_country">Education Country</option>
<option value="education_start_date">Education Start Date</option>
<option value="education_end_date">Education End Date</option>
<option value="graduation_date">Graduation Date</option>
<option value="degree" >Degree</option>
</optgroup>
<optgroup label="Provider Information"></optgroup>
<optgroup style="margin-left:12px;" label="Address">
<option value="full_address">Full Address</option>
<option value="address_1">Address 1</option>
<option value="address_2">Address 2</option>
<option value="address_city">City</option>
<option value="address_county">County</option>
<option value="address_state">State</option>
<option value="address_zip_code">Zipcode</option>
<option value="address_country">Country</option>
<option value="address_csz">City/State/Zip</option>
</optgroup>
<optgroup style="margin-left:12px;" label="Phone">
<option value="phone_number">Number</option>
<option value="phone_extension">Extension</option>
</optgroup>
<optgroup style="margin-left:12px;" label="Singular Values">
<option value="url">URL</option>
<option value="tin">TIN Number</option>
<option value="email">Email</option>
<option value="dea_registration_number">DEA Regisration Number</option>
<option value="npi_number">NPI Number</option>
<option value="upin_number">UPIN Number</option>
</optgroup>
<optgroup style="margin-left:12px;" label="Provider Values">
<option value="provider_value">Provider Value</option>
</optgroup>
</select>
...And this is not even the entire select object. In the W-3 tutorial it builds each element independently as variables and adds them to each other individually. As you can see this might take some time to write and just seems very bulky. I would like to define the select object once and have it replicated that way (if possible) with every click. I imagine each newly created select object would need a unique name, but I am not 100% sure on that. If that is the case, is there a way to just append a 1 to the name of the first one and so on?

If you want something in jQuery you can use clone() function. See:
$("#data_value_selector").clone().appendTo("#select-box");
Demo.
I changed the name attribute to send a collection of the selected values. You can change this behaviour to a custom name in the click event, if you want:
var newSelect = $("#data_value_selector").clone();
newSelect.attr("name", "newName");
newSelect.appendTo("#select-box");
I hope this helps you.

You could use the cloneNode() method. Here is an example:
http://jsfiddle.net/JKNT4/7/
HTML
<button onclick="addRow()">Add Row</button>
<div id="parent_selector" class="data-row">
<select name="data_value[]">
<option>1</option>
<option>2</option>
<option>3</option>
</select>
</div>
<div id="child_selectors"></div>
Javascript
function addRow() {
var itm = document.getElementById("parent_selector");
var cln = itm.cloneNode(true);
cln.removeAttribute("id");
document.getElementById("child_selectors").appendChild(cln);
}