Laravel 5.6: How to pass selected value from Dropdown list to PHP variable on the same page by Ajax

I'm using Laravel 5.6 and PHP 7.1.9. I Have this selected box, and the PHP condition on the same page to check the value of checkbox selected, and then to do some tasks:

 <select name="" id="">
                    <option value="All" disabled selected>All Status</option>
                    <option value="Available">Available</option>
                    <option value="Not Available">Not Available</option>
                    <option value="Partial Available">Partial Available</option>

                </select>


@if($The_DropDownList_Value == "Available")
     
@endif


@if($The_DropDownList_Value == "Not Available")
     
@endif

I want to pass the selected value to the PHP variable ($The_DropDownList_Value )by using Ajax and JS. How to get the Selected value box and pass it to PHP variable to check the value and to some tasks in the condition.

Thanks

via Chebli Mohamed