自动选择第一个下拉选项

Question

基于此代码：http://jsfiddle.net/3UWk2/3/

<select size="1" id="Rank" title="" name="Rank"> 
<option value="">-Select Your Rank-</option> 
<option value="airman">Airman</option> 
<option value="senior-airman">Senior Airman</option> 
</select> 

<div class="container"> 
<div class="airman"> 
    <select class="second-level-select"> 
     <option value="">-Select Your Rank-</option> 
     <option value="basic-ore-1">Basic Ore Miner - Level 1</option> 
     <option value="basic-ore-2">Basic Ore Miner - Level 2</option> 
    </select> 
</div> 
<div class="senior-airman"> 
    <select class="second-level-select"> 
     <option value="">-Select Your Rank-</option> 
     <option value="omber-miner-1">Omber Miner - Level 1</option> 
     <option value="omber-miner-2">Omber Miner - Level 2</option> 
    </select> 
</div> 
</div> 

<div class="second-level-container"> 
<div class="basic-ore-1"> 
    Line of text for basic ore miner 1 
</div> 
<div class="basic-ore-2"> 
    Line of text for basic ore miner 2 
</div> 
<div class="omber-miner-1"> 
    Line of text for omber miner 1 
</div> 
<div class="omber-miner-2"> 
    Line of text for omber miner 2 
</div>  
</div> 

依次为：

$(document).ready(function() { 
$('#Rank').bind('change', function() { 
    var elements = $('div.container').children().hide(); // hide all the elements 
    var value = $(this).val(); 

    if (value.length) { // if somethings' selected 
     elements.filter('.' + value).show(); // show the ones we want 
    } 
}).trigger('change'); 

$('.second-level-select').bind('change', function() { 
    var elements = $('div.second-level-container').children().hide(); // hide all the elements 
    var value = $(this).val(); 

    if (value.length) { // if somethings' selected 
     elements.filter('.' + value).show(); // show the ones we want 
    } 
}).trigger('change'); 
}); 

如何自动选择两个下拉列表的第一个选项，显示最终值的OnLoad？

我正在寻找3乘3下降，共有9个值。

Answer 1

检查，这可能帮助你

$(document).ready(function() { 
 
//bind onchange for the rank dd 
 
    $("#Rank").on('change', function() { 
 
    let selectedValue = $(this).val(); 
 
    $(".container>div").hide(); 
 
    if (selectedValue.length) { 
 
     $("." + selectedValue).show(); 
 
     //select.val($(select + " option:eq(1)").val()); 
 
    } 
 
    }) 
 
//bind onchange for the airman dd 
 
    $("#second-level-select-airman").on('change', function() { 
 
    let selectedValue = $(this).val(); 
 
    $(".second-level-container").children().hide(); 
 

 

 
    if (selectedValue.length) { 
 
     $("." + selectedValue).show(); 
 
     //select.val($(select + " option:eq(1)").val()); 
 
    } 
 
    }) 
 
//bind onchange for the senior airman 
 
    $("#second-level-select-senior-airman").on('change', function() { 
 
    let selectedValue = $(this).val(); 
 
    $(".second-level-container").children().hide(); 
 

 

 
    if (selectedValue.length) { 
 
     $("." + selectedValue).show(); 
 
     //select.val($(select + " option:eq(1)").val()); 
 
    } 
 
    }); 
 
    //select first value of first dropdown 
 
    $("#Rank").val($("#Rank option:eq(1)").val()).trigger('change'); 
 
    
 
    //select the first option from the 2nd menu depending on the valur of the first dd 
 
    $("." + $("#Rank").val()).find("select").val(
 
    $("." + $("#Rank").val()).find("select option:eq(1)").val() 
 
).trigger('change'); 
 
    // $("#Rank").val($("#Rank option:eq(1)").val()); 
 
    // $("." + $("#Rank").val()).find("select").val(
 
    //  $("." + $("#Rank").val()).find("select option:eq(1)").val() 
 
    //); 
 
});

.airman, 
 
.senior-airman, 
 
.second-level-container>div { 
 
    display: none; 
 
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
 
<select id="Rank" name="Rank"> 
 
      <option value="">-Select Your Rank-</option> 
 
      <option value="airman">Airman</option> 
 
      <option value="senior-airman">Senior Airman</option> 
 
     </select> 
 

 
<div class="container"> 
 
    <div class="airman"> 
 
    <select class="second-level-select" id="second-level-select-airman"> 
 
        <option value="">-Select Your Rank-</option> 
 
        <option value="basic-ore-1">Basic Ore Miner - Level 1</option> 
 
        <option value="basic-ore-2">Basic Ore Miner - Level 2</option> 
 
       </select> 
 
    </div> 
 
    <div class="senior-airman"> 
 
    <select class="second-level-select" id="second-level-select-senior-airman"> 
 
        <option value="">-Select Your Rank-</option> 
 
        <option value="omber-miner-1">Omber Miner - Level 1</option> 
 
        <option value="omber-miner-2">Omber Miner - Level 2</option> 
 
       </select> 
 
    </div> 
 
</div> 
 

 
<div class="second-level-container"> 
 
    <div class="basic-ore-1"> 
 
    Line of text for basic ore miner 1 
 
    </div> 
 
    <div class="basic-ore-2"> 
 
    Line of text for basic ore miner 2 
 
    </div> 
 
    <div class="omber-miner-1"> 
 
    Line of text for omber miner 1 
 
    </div> 
 
    <div class="omber-miner-2"> 
 
    Line of text for omber miner 2 
 
    </div> 
 
</div>