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代码很长。但是从我的观点来看，为了展示什么是必要的，我必须发布整个代码。

三个下拉菜单。使用php和javascript。如果其中一个菜单更改了值，则将其他两个菜单中的值设置为默认值。

创建了需要改进/优化的长代码（需要使用 JavaScript 来缩短）。

在此处发布代码（不含 php）http://jsfiddle.net/rigaconnect/QaUmK/5/（由于无法理解的原因，在 jsfiddle 中发布的代码无法完全正常工作；在我的网站上，代码按预期工作。）

一开始php

$options_month = array("Select month", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December");
$options_quarter = array("Select quarter", "First", "Second", "Third", "Fourth");
$options_halfyear = array("Select half-year", "First", "Second");

然后下拉菜单

<select id="month_id" name="monthid">
<?php
foreach ( $options_month as $i1=>$opt1 ) : 
echo '<option value="' .htmlspecialchars($i1) .'"' .((htmlspecialchars($i1) == htmlspecialchars($_POST['monthid'][$counter]))? 'selected' : "") .'>'.htmlspecialchars($opt1) .'</option>';
endforeach;
?>
</select>

<select id="quarter_id" name="quarterid">
<?php
foreach ( $options_quarter as $i1=>$opt1 ) : 
echo '<option value="' .htmlspecialchars($i1) .'"' .((htmlspecialchars($i1) == htmlspecialchars($_POST['quarterid'][$counter]))? 'selected' : "") .'>'.htmlspecialchars($opt1) .'</option>';
endforeach;
?>
</select>

<select id="halfyear_id" name="halfyearid">
<?php
foreach ( $options_halfyear as $i1=>$opt1 ) : 
echo '<option value="' .htmlspecialchars($i1) .'"' .((htmlspecialchars($i1) == htmlspecialchars($_POST['halfyear'][$counter]))? 'selected' : "") .'>'.htmlspecialchars($opt1) .'</option>';
endforeach;
?>
</select>

然后是需要改进的javascript。代码很长。较短的代码可能也是如此。

var month_for_update = document.getElementById( 'month_id' );
function updateQuarterHalfyear ( e ) {

var quarter = this.options[ this.selectedIndex ].value, quarterDDL= document.getElementById( 'quarter_id' ), quarter, i = quarterDDL.options.length - 1;

var halfyear = this.options[ this.selectedIndex ].value, halfyearDDL= document.getElementById( 'halfyear_id' ), halfyear, i = halfyearDDL.options.length - 1;

quarter = 0;
halfyear = 0;

for ( ; i > -1 ; i-- ) {
if ( quarterDDL.options[i].value == quarter ) {
quarterDDL.options[i].selected = true;
break;
}
}

for ( ; i > -1 ; i-- ) {
if ( halfyearDDL.options[i].value == halfyear ) {
halfyearDDL.options[i].selected = true;
break;
}
}

}

month_for_update.onchange = updateQuarterHalfyear;

/**/
var quarter_for_update = document.getElementById( 'quarter_id' );
function updateMonthHalfyear ( e ) {

var month = this.options[ this.selectedIndex ].value, monthDDL= document.getElementById( 'month_id' ), month, i = monthDDL.options.length - 1;

var halfyear = this.options[ this.selectedIndex ].value, halfyearDDL= document.getElementById( 'halfyear_id' ), halfyear, i = halfyearDDL.options.length - 1;

month = 0;
halfyear = 0;

for ( ; i > -1 ; i-- ) {
if ( monthDDL.options[i].value == month ) {
monthDDL.options[i].selected = true;
break;
}
}

for ( ; i > -1 ; i-- ) {
if ( halfyearDDL.options[i].value == halfyear ) {
halfyearDDL.options[i].selected = true;
break;
}
}

}

quarter_for_update.onchange = updateMonthHalfyear;


/**/
var halfyear_for_update = document.getElementById( 'halfyear_id' );
function updateMonthQuarter ( e ) {

var month = this.options[ this.selectedIndex ].value, monthDDL= document.getElementById( 'month_id' ), month, i = monthDDL.options.length - 1;

var quarter = this.options[ this.selectedIndex ].value, quarterDDL= document.getElementById( 'quarter_id' ), quarter, i = quarterDDL.options.length - 1;

month = 0;
quarter = 0;

for ( ; i > -1 ; i-- ) {
if ( monthDDL.options[i].value == month ) {
monthDDL.options[i].selected = true;
break;
}
}

for ( ; i > -1 ; i-- ) {
if ( quarterDDL.options[i].value == quarter ) {
quarterDDL.options[i].selected = true;
break;
}
}

}

halfyear_for_update.onchange = updateMonthQuarter;

请建议如何缩短 javascript。可能可以改进代码的其他部分。

澄清。默认值为 , , 中的第一个值( [0]) 。首次加载页面时可以看到, , . 所以页面加载。用户例如从月份下拉菜单中选择。然后用户决定选择季度而不是月份。用户从宿舍下拉菜单中选择。月值下拉菜单自动更改为。$options_month$options_quarter$options_halfyearSelect monthSelect quarterSelect half-yearFebruaryFirstSelect month

4

1 回答 1

1

这是我的解决方案。简单得多。但是，我也更改了 html 布局。

HTML 更新：（在选择标签中有 onchange）

<select id="month_id" name="monthid" onchange="update_other_dd ( 'month_id' )">
...
<select id="quarter_id" name="quarterid" onchange="update_other_dd ( 'quarter_id' )">
...
<select id="halfyear_id" name="halfyearid" onchange="update_other_dd ( 'halfyear_id' )">
...

Javascript 更新：（减少到 9 行）

    var dd_array = ['month_id', 'quarter_id', 'halfyear_id'];
    function update_other_dd ( dd_id ) {
    for(i=0;i<dd_array.length;i++){
    if(dd_array[i] != dd_id){
        var array_to_reset = document.getElementById( dd_array[i] );
        array_to_reset.options[0].selected = 1;
    }
    }
    }
于 2013-07-26T20:50:28.560 回答