Two listboxes with equal width in one container div

Question

I try to create complex control in my online application. Control have two listboxes and two buttons between. Width of listboxes (listbox-target, listbox-source) must be equal. Width of control-buttons can be fixed. Height of all controls must be equal too. HTML and JS code below.

I try to make this with css, but can't. I wrote javascript to calculacte width and height of each element.

Width of listbox-target = listbox-source = ('fullwidth of attributeref-two-listboxes' - 'width of control-buttons') / 2. 

It work good, but must be called everytime from resize event. Sometimes resize event is not fire and width of controls not change.

I think, best of all is make this with css only, but how?! Please, help!

function resizeAttributerefTwoListboxes() {
var is_ff = navigator.userAgent.toLowerCase().indexOf('firefox') > -1,
    is_ie = navigator.userAgent.toLowerCase().indexOf('MSIE') > -1 || /Trident.*rv[ :]*(\d+\.\d+)/.test(navigator.userAgent);
$("div.attributeref-two-listboxes div").removeAttr("style");
$("div.attributeref-two-listboxes").each(function(){
    var that = $(this),
        target = that.find(".listbox-target"),
        source = that.find(".listbox-source"),
        control = that.find(".control-buttons");
    if (this.offsetWidth < 420) {
        control.find('a[method="add"] > i').addClass("fa-angle-up").removeClass("fa-angle-left");
        control.find('a[method="remove"] > i').addClass("fa-angle-down").removeClass("fa-angle-right");
        target.css({"width":"100%"});
        control.css({"width":"100%"});
        control.children().css({"display":"inline-block"});
        source.css({"width":"100%"});
    } else {    //horizontal alignment
        control.find('a[method="add"] > i').addClass("fa-angle-left").removeClass("fa-angle-up");
        control.find('a[method="remove"] > i').addClass("fa-angle-right").removeClass("fa-angle-down");
        var w = Math.ceil((this.offsetWidth - control[0].offsetWidth - (is_ff || is_ie ? 2 : 1))/2);
        target.css({"width":w+"px"});
        source.css({"width":w+"px"});
        control.children().css({"height":(target[0].offsetHeight-20)+"px"}); //20 - paddings from top and bottom (10+10)
        control.css({"height":target[0].offsetHeight+"px"});
    }
});
}

<div class="attributeref-two-listboxes">
<div class="listbox-target" style="width: 549px;">
    <select id="Objectint_chg_management_change_user" acode="chg_management_change_user" atype="8" astyle="3" aislist="0" class="form-control tooltipstered" multiple="multiple" style="max-width: 750px;" size="4" name="Objectint[chg_management_change_user][]"></select>
</div>
<div class="control-buttons" style="height: 90px;">
    <div style="height: 70px;">
        <a class="btn btn-primary option mover" target="Objectint_chg_management_change_user" source="Objectint_chg_management_change_user_select" method="add" href="#">
            <i class="fa fa-angle-left"></i>
        </a>
        <a class="btn btn-primary option mover" target="Objectint_chg_management_change_user" source="Objectint_chg_management_change_user_select" method="remove" href="#">
            <i class="fa fa-angle-right"></i>
        </a>
    </div>
</div>
<div class="listbox-source" style="width: 549px;">
    <select id="Objectint_chg_management_change_user_select" acode="chg_management_change_user" atype="8" astyle="3" aislist="0" class="form-control" multiple="multiple" style="max-width: 750px;" size="4" name="[]">
        <option value="68">User 1</option>
        <option value="61">User 2</option>
        <option value="76">User 3</option>
    </select>
</div>

this is my control after right resize

this is my control after wrong resize

Answer 1

Use float: left and min-width .

The min-width should be at least the widths of the elements. If the section can span the entire width of the page, using 960px is not a bad idea because it displays well in most form factors (tablets, smartphones, PCs, occupies 1/2 of a 1080p display).

This way you can also avoid using display: inline-block which is not supported in older browsers (though that window keeps sliding forward so this isn't much of a problem these days except for enterprise web apps,etc.).

 .attributeref-two-listboxes { min-width: 960px; overflow: hidden; font-size: 0; } .chooser { float: left; width: 300px; height: 100px; font-size: 14px; } .buttons { float: left; } .buttons input { width: 30px; height: 30px; background-color: rgb(34,131,203); color: #fff; border: 1px solid #333; display: block; margin: 13px 16px; font-size: 16px; } 

 <div class="attributeref-two-listboxes"> <select multiple size=4 class='chooser'> <option>Uno</option> <option>Dos</option> <option>Tres</option> </select> <div class='buttons'> <input type='button' value='&lt;' /> <input type='button' value='&gt;' /> </div> <select multiple size=4 class='chooser'> <option>Uno</option> <option>Dos</option> <option>Tres</option> </select> </div> 

Answer 2

Flex-box allow to avoid using JS in some cases like your.

Link to jsfiddle .

@media screen and (max-width: 500px) {
    .flex_container {
        flex-direction: column;
        flex-basis: 100%;
    }
.arrays_v {display : none}
.arrays_h {display : inline}    
}

I suppose my my solution will be useful for you.