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Remove select placeholder on focus select field

<select class="name">
<option value="">Select Option</option>
<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>
Remove Select Option when user click on it like input field placeholder. Also not show in drop down.

<select class="name">
<option value="" style="display:none;">Select Option</option>
<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>
style="display:none;" should do the trick (Selected by default but not visible under options).

You can instated use <option value="" disabled selected>Select Option</option>

Change multiple dropdown values by selecting from a single dropdown

As the title says, Im trying to change the values on multiple dropdowns by changing a single dropdown. The multiple dropdowns need to get the same value that is selected in the "Select All" dropdown. Something very similar to a check all for checkboxes.
<select name="changeAll" id="changeAll" onchange="changeAll(this);">
<option value="select" selected="selected">Select</option>
<option value="option1">Option 1</option>
<option value="option2">Option 2</option>
<option value="option3">Option 3</option>
</select>
<select id="currency1" class="form-control">
<option selected value="option1" disabled>Option 1</option>
<option value="option1">Option 1</option>
<option value="option2">Option 2</option>
<option value="option3">Option 3</option>
</select>
<select id="currency2" class="form-control">
<option selected value="option1" disabled>Option 1</option>
<option value="option1">Option 1</option>
<option value="option2">Option 2</option>
<option value="option3">Option 3</option>
</select>
<select id="currency3" class="form-control">
<option selected value="option1" disabled>Option 1</option>
<option value="option1">Option 1</option>
<option value="option2">Option 2</option>
<option value="option3">Option 3</option>
</select>
The idea is that when a value is selected in the first dropdown "changeAll", all of the other dropdowns will have their values change to match the one selected in the "changeAll" dropdown.
Any help with this would be greatly appreciated.

Based on what you asked, I have tried to simulate. Try to run. Thnx
$('select#changeAll').on('change', function() {
var val_ = $('#changeAll :selected').text();
$('.child-changed option').map(function() {
$(this).text(val_);
$(this).value=val_;
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div>
<select name="changeAll" id="changeAll" >
<option value="ca_select" selected="selected">Select</option>
<option value="ca_option1">ca Option 1</option>
<option value="ca_option2">ca Option 2</option>
<option value="ca_option3">ca Option 3</option>
</select>
<div>
</div>
<select id="currency1" class="form-control child-changed">
<option selected value="c1_option1_selected" disabled>currency1 Option 1</option>
<option value="c1_option1">currency1 Option 1</option>
<option value="c1_option2">currency1 Option 2</option>
<option value="c1_option3">currency1 Option 3</option>
</select>
<div>
</div>
<select id="currency2" class="form-control child-changed">
<option selected value="c2_option1_selected" disabled>currency2 Option 1</option>
<option value="c2_option1">currency2 Option 1</option>
<option value="c2_option2">currency2 Option 2</option>
<option value="c2_option3">currency2 Option 3</option>
</select>
<div>

Add third list on dependent dropdown list JS

I'm trying to create a dynamic dependent drop down lists. This code below work fine with 2 dependency and I’m trying to add a third dependency. Have you got any idea ?
For exemple :
Status 1 = offer 1, offer 2, offer 3 , offer 4
Offer 1 = Option 1
Thanks for your help
UPDATE 11.15.09
Finally find a solution
$("#street").val([]);
$('#street option').hide();
$("#city").on("change", function() {
$('#street option')
.hide() // hide all
.filter('[value^="' + $(this).val() + '"]') // filter options with required value
.show(); // and show them
$("#street").val([]);
})
$("#number").val([]);
$('#number option').hide();
$("#street").on("change", function() {
$('#number option')
.hide() // hide all
.filter('[value^="' + $(this).val() + '"]') // filter options with required value
.show(); // and show them
$("#number").val([]);
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
City:
<select id="city" name="city">
<option value="0">Select City</option>
<option value="1">Manchester</option>
<option value="2">Leicester</option>
<option value="3">Londra</option>
</select>
Street:
<select id="street" name="street">
<option value="1.A">Street A</option>
<option value="1.B">Street B</option>
<option value="1.C">Street C</option>
<option value="2.D">Street D</option>
<option value="2.E">Street E</option>
<option value="2.F">Street F</option>
<option value="3.G">Street G</option>
<option value="3.H">Street H</option>
</select>
Number:
<select id="number" name="number">
<option value="1.A">1</option>
<option value="1.B">2</option>
<option value="1.C">3</option>
<option value="2.D">4</option>
<option value="2.E">5</option>
</select>

I fixed the problem with javascript. (no need to use jQuery)
Please try to use updated code below.
HTML:
<div>
<select name="select1" id="select1">
<option value="1" data-sync="1">Status 1</option>
<option value="2" data-sync="2">Status 2</option>
</select>
</div>
<div>
<select name="select2" id="select2">
<option value="1">offer 1</option>
<option value="1">offer 2</option>
<option value="1">offer 3</option>
<option value="1">offer 4</option>
<option value="1">offer 5</option>
<option value="2">offer 6</option>
<option value="2">offer 7</option>
<option value="2">offer 8</option>
<option value="2">offer 9<option>
</select>
</div>
<div>
<select name="select3" id="select3">
<option value="1">option 1</option>
<option value="2">option 2</option>
<option value="1">option 3</option>
<option value="2">option 4</option>
</select>
</div>
Javascript:
document.getElementById("select1").onchange=function() {
document.getElementById("select2").value=this.options[this.selectedIndex].getAttribute("data-sync");
document.getElementById("select3").value=this.options[this.selectedIndex].getAttribute("data-sync");
}
document.getElementById("select1").onchange();
Check the running code link below.
http://jsfiddle.net/f97u5nLa/33/

How can i manage all selectbox when onchange in any one of them?

I have listing week days on my web page and every day have a select box as like below
<select name="day1" >
<option value="">select</option>
<option value="1">Text 1</option>
<option value="2">Text 2</option>
<option value="3">Text 3</option>
</select>
<select name="day2" >
<option value="">select</option>
<option value="1">Text 1</option>
<option value="2">Text 2</option>
<option value="3">Text 3</option>
</select>
<select name="day3" >
<option value="">select</option>
<option value="1">Text 1</option>
<option value="2">Text 2</option>
<option value="3">Text 3</option>
</select>
.
.
.
.
Here if i select any option from "day2" then how can i make all others select box value default or null, as well as if i select with "day1" then day2 and day3 should be default or null using jQuery

Just create a change listener on all select and change every element what is not() itself.
$("select").change(function() {
$("select").not(this).val("");
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select name="day1">
<option value="">select</option>
<option value="1">Text 1</option>
<option value="2">Text 2</option>
<option value="3">Text 3</option>
</select>
<select name="day2">
<option value="">select</option>
<option value="1">Text 1</option>
<option value="2">Text 2</option>
<option value="3">Text 3</option>
</select>
<select name="day3">
<option value="">select</option>
<option value="1">Text 1</option>
<option value="2">Text 2</option>
<option value="3">Text 3</option>
</select>

How to make chosen menu disabled by default

Here, I have an example of jquery-chosen with modal dialog. What I want is on first open of the dialog, the chosen to not show the items. I read the documentation and I don't find anything.
So in the current example the modal options should be closed after running the fiddle example:
HTML
<div id="dialog">
<label for="options1">Modal Options</label>
<select id="options1" multiple="multiple">
<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>
<option value="6">Option 6</option>
<option value="7">Option 7</option>
</select>
</div>
<label for="options1">Options</label>
<select id="options2">
<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>
<option value="6">Option 6</option>
<option value="7">Option 7</option>
</select>
JS
$(function(){
$("select").chosen();
$("#dialog").dialog({modal: true, width:400, height:"auto"});
});

Call jQuery chosen after calling dialog.
$(function(){
$("#dialog").dialog({modal: true, width:400, height:"auto"});
$("select").chosen();
});