如何为此下拉菜单创建循环

那么，循环会比逐一列出它们更有效吗？

<select name="birthdayYear" >
    <option value="0000"<?php echo $birthdayYear == '0000' ? 'selected="selected"' : ''; ?>>Year:</option>
    <option value="2011"<?php echo $birthdayYear == '2011' ? 'selected="selected"' : ''; ?>>2011</option>
    <option value="2010"<?php echo $birthdayYear == '2010' ? 'selected="selected"' : ''; ?>>2010</option>
    <option value="2009"<?php echo $birthdayYear == '2009' ? 'selected="selected"' : ''; ?>>2009</option>
    <option value="2008"<?php echo $birthdayYear == '2008' ? 'selected="selected"' : ''; ?>>2008</option>
    <option value="2007"<?php echo $birthdayYear == '2007' ? 'selected="selected"' : ''; ?>>2007</option>
    <option value="2006"<?php echo $birthdayYear == '2006' ? 'selected="selected"' : ''; ?>>2006</option>
    <option value="2005"<?php echo $birthdayYear == '2005' ? 'selected="selected"' : ''; ?>>2005</option>
    <option value="2004"<?php echo $birthdayYear == '2004' ? 'selected="selected"' : ''; ?>>2004</option>
    <option value="2003"<?php echo $birthdayYear == '2003' ? 'selected="selected"' : ''; ?>>2003</option>
    <option value="2002"<?php echo $birthdayYear == '2002' ? 'selected="selected"' : ''; ?>>2002</option>
    <option value="2001"<?php echo $birthdayYear == '2001' ? 'selected="selected"' : ''; ?>>2001</option>
    <option value="2000"<?php echo $birthdayYear == '2000' ? 'selected="selected"' : ''; ?>>2000</option>
    <option value="1999"<?php echo $birthdayYear == '1999' ? 'selected="selected"' : ''; ?>>1999</option>
    <option value="1998"<?php echo $birthdayYear == '1998' ? 'selected="selected"' : ''; ?>>1998</option>
    <option value="1997"<?php echo $birthdayYear == '1997' ? 'selected="selected"' : ''; ?>>1997</option>
    <option value="1996"<?php echo $birthdayYear == '1996' ? 'selected="selected"' : ''; ?>>1996</option>
    <option value="1995"<?php echo $birthdayYear == '1995' ? 'selected="selected"' : ''; ?>>1995</option>
    <option value="1994"<?php echo $birthdayYear == '1994' ? 'selected="selected"' : ''; ?>>1994</option>
    <option value="1993"<?php echo $birthdayYear == '1993' ? 'selected="selected"' : ''; ?>>1993</option>
    <option value="1992"<?php echo $birthdayYear == '1992' ? 'selected="selected"' : ''; ?>>1992</option>
    <option value="1991"<?php echo $birthdayYear == '1991' ? 'selected="selected"' : ''; ?>>1991</option>
    <option value="1990"<?php echo $birthdayYear == '1990' ? 'selected="selected"' : ''; ?>>1990</option>
    <option value="1989"<?php echo $birthdayYear == '1989' ? 'selected="selected"' : ''; ?>>1989</option>
    <option value="1988"<?php echo $birthdayYear == '1988' ? 'selected="selected"' : ''; ?>>1988</option>
    <option value="1987"<?php echo $birthdayYear == '1987' ? 'selected="selected"' : ''; ?>>1987</option>
    <option value="1986"<?php echo $birthdayYear == '1986' ? 'selected="selected"' : ''; ?>>1986</option>
    <option value="1985"<?php echo $birthdayYear == '1985' ? 'selected="selected"' : ''; ?>>1985</option>
    <option value="1984"<?php echo $birthdayYear == '1984' ? 'selected="selected"' : ''; ?>>1984</option>
    <option value="1983"<?php echo $birthdayYear == '1983' ? 'selected="selected"' : ''; ?>>1983</option>
    <option value="1982"<?php echo $birthdayYear == '1982' ? 'selected="selected"' : ''; ?>>1982</option>
    <option value="1981"<?php echo $birthdayYear == '1981' ? 'selected="selected"' : ''; ?>>1981</option>
    <option value="1980"<?php echo $birthdayYear == '1980' ? 'selected="selected"' : ''; ?>>1980</option>
    <option value="1979"<?php echo $birthdayYear == '1979' ? 'selected="selected"' : ''; ?>>1979</option>
    <option value="1978"<?php echo $birthdayYear == '1978' ? 'selected="selected"' : ''; ?>>1978</option>
    <option value="1977"<?php echo $birthdayYear == '1977' ? 'selected="selected"' : ''; ?>>1977</option>
    <option value="1976"<?php echo $birthdayYear == '1976' ? 'selected="selected"' : ''; ?>>1976</option>
    <option value="1975"<?php echo $birthdayYear == '1975' ? 'selected="selected"' : ''; ?>>1975</option>
    <option value="1974"<?php echo $birthdayYear == '1974' ? 'selected="selected"' : ''; ?>>1974</option>
    <option value="1973"<?php echo $birthdayYear == '1973' ? 'selected="selected"' : ''; ?>>1973</option>
    <option value="1972"<?php echo $birthdayYear == '1972' ? 'selected="selected"' : ''; ?>>1972</option>
    <option value="1971"<?php echo $birthdayYear == '1971' ? 'selected="selected"' : ''; ?>>1971</option>
    <option value="1970"<?php echo $birthdayYear == '1970' ? 'selected="selected"' : ''; ?>>1970</option>
    <option value="1969"<?php echo $birthdayYear == '1969' ? 'selected="selected"' : ''; ?>>1969</option>
    <option value="1968"<?php echo $birthdayYear == '1968' ? 'selected="selected"' : ''; ?>>1968</option>
    <option value="1967"<?php echo $birthdayYear == '1967' ? 'selected="selected"' : ''; ?>>1967</option>
    <option value="1966"<?php echo $birthdayYear == '1966' ? 'selected="selected"' : ''; ?>>1966</option>
    <option value="1965"<?php echo $birthdayYear == '1965' ? 'selected="selected"' : ''; ?>>1965</option>
    <option value="1964"<?php echo $birthdayYear == '1964' ? 'selected="selected"' : ''; ?>>1964</option>
    <option value="1963"<?php echo $birthdayYear == '1963' ? 'selected="selected"' : ''; ?>>1963</option>
    <option value="1962"<?php echo $birthdayYear == '1962' ? 'selected="selected"' : ''; ?>>1962</option>
    <option value="1961"<?php echo $birthdayYear == '1961' ? 'selected="selected"' : ''; ?>>1961</option>
    <option value="1960"<?php echo $birthdayYear == '1960' ? 'selected="selected"' : ''; ?>>1960</option>
    <option value="1959"<?php echo $birthdayYear == '1959' ? 'selected="selected"' : ''; ?>>1959</option>
    <option value="1958"<?php echo $birthdayYear == '1958' ? 'selected="selected"' : ''; ?>>1958</option>
    <option value="1957"<?php echo $birthdayYear == '1957' ? 'selected="selected"' : ''; ?>>1957</option>
    <option value="1956"<?php echo $birthdayYear == '1956' ? 'selected="selected"' : ''; ?>>1956</option>
    <option value="1955"<?php echo $birthdayYear == '1955' ? 'selected="selected"' : ''; ?>>1955</option>
    <option value="1954"<?php echo $birthdayYear == '1954' ? 'selected="selected"' : ''; ?>>1954</option>
    <option value="1953"<?php echo $birthdayYear == '1953' ? 'selected="selected"' : ''; ?>>1953</option>
    <option value="1952"<?php echo $birthdayYear == '1952' ? 'selected="selected"' : ''; ?>>1952</option>
    <option value="1951"<?php echo $birthdayYear == '1951' ? 'selected="selected"' : ''; ?>>1951</option>
    <option value="1950"<?php echo $birthdayYear == '1950' ? 'selected="selected"' : ''; ?>>1950</option>
    <option value="1949"<?php echo $birthdayYear == '1949' ? 'selected="selected"' : ''; ?>>1949</option>
    <option value="1948"<?php echo $birthdayYear == '1948' ? 'selected="selected"' : ''; ?>>1948</option>
    <option value="1947"<?php echo $birthdayYear == '1947' ? 'selected="selected"' : ''; ?>>1947</option>
    <option value="1946"<?php echo $birthdayYear == '1946' ? 'selected="selected"' : ''; ?>>1946</option>
    <option value="1945"<?php echo $birthdayYear == '1945' ? 'selected="selected"' : ''; ?>>1945</option>
    <option value="1944"<?php echo $birthdayYear == '1944' ? 'selected="selected"' : ''; ?>>1944</option>
    <option value="1943"<?php echo $birthdayYear == '1943' ? 'selected="selected"' : ''; ?>>1943</option>
    <option value="1942"<?php echo $birthdayYear == '1942' ? 'selected="selected"' : ''; ?>>1942</option>
    <option value="1941"<?php echo $birthdayYear == '1941' ? 'selected="selected"' : ''; ?>>1941</option>
    <option value="1940"<?php echo $birthdayYear == '1940' ? 'selected="selected"' : ''; ?>>1940</option>
    <option value="1939"<?php echo $birthdayYear == '1939' ? 'selected="selected"' : ''; ?>>1939</option>
    <option value="1938"<?php echo $birthdayYear == '1938' ? 'selected="selected"' : ''; ?>>1938</option>
    <option value="1937"<?php echo $birthdayYear == '1937' ? 'selected="selected"' : ''; ?>>1937</option>
    <option value="1936"<?php echo $birthdayYear == '1936' ? 'selected="selected"' : ''; ?>>1936</option>
    <option value="1935"<?php echo $birthdayYear == '1935' ? 'selected="selected"' : ''; ?>>1935</option>
    <option value="1934"<?php echo $birthdayYear == '1934' ? 'selected="selected"' : ''; ?>>1934</option>
    <option value="1933"<?php echo $birthdayYear == '1933' ? 'selected="selected"' : ''; ?>>1933</option>
    <option value="1932"<?php echo $birthdayYear == '1932' ? 'selected="selected"' : ''; ?>>1932</option>
    <option value="1931"<?php echo $birthdayYear == '1931' ? 'selected="selected"' : ''; ?>>1931</option>
    <option value="1930"<?php echo $birthdayYear == '1930' ? 'selected="selected"' : ''; ?>>1930</option>
    <option value="1929"<?php echo $birthdayYear == '1929' ? 'selected="selected"' : ''; ?>>1929</option>
    <option value="1928"<?php echo $birthdayYear == '1928' ? 'selected="selected"' : ''; ?>>1928</option>
    <option value="1927"<?php echo $birthdayYear == '1927' ? 'selected="selected"' : ''; ?>>1927</option>
    <option value="1926"<?php echo $birthdayYear == '1926' ? 'selected="selected"' : ''; ?>>1926</option>
    <option value="1925"<?php echo $birthdayYear == '1925' ? 'selected="selected"' : ''; ?>>1925</option>
    <option value="1924"<?php echo $birthdayYear == '1924' ? 'selected="selected"' : ''; ?>>1924</option>
    <option value="1923"<?php echo $birthdayYear == '1923' ? 'selected="selected"' : ''; ?>>1923</option>
    <option value="1922"<?php echo $birthdayYear == '1922' ? 'selected="selected"' : ''; ?>>1922</option>
    <option value="1921"<?php echo $birthdayYear == '1921' ? 'selected="selected"' : ''; ?>>1921</option>
    <option value="1920"<?php echo $birthdayYear == '1920' ? 'selected="selected"' : ''; ?>>1920</option>
    <option value="1919"<?php echo $birthdayYear == '1919' ? 'selected="selected"' : ''; ?>>1919</option>
    <option value="1918"<?php echo $birthdayYear == '1918' ? 'selected="selected"' : ''; ?>>1918</option>
    <option value="1917"<?php echo $birthdayYear == '1917' ? 'selected="selected"' : ''; ?>>1917</option>
    <option value="1916"<?php echo $birthdayYear == '1916' ? 'selected="selected"' : ''; ?>>1916</option>
    <option value="1915"<?php echo $birthdayYear == '1915' ? 'selected="selected"' : ''; ?>>1915</option>
    <option value="1914"<?php echo $birthdayYear == '1914' ? 'selected="selected"' : ''; ?>>1914</option>
    <option value="1913"<?php echo $birthdayYear == '1913' ? 'selected="selected"' : ''; ?>>1913</option>
    <option value="1912"<?php echo $birthdayYear == '1912' ? 'selected="selected"' : ''; ?>>1912</option>
    <option value="1911"<?php echo $birthdayYear == '1911' ? 'selected="selected"' : ''; ?>>1911</option>
    <option value="1910"<?php echo $birthdayYear == '1910' ? 'selected="selected"' : ''; ?>>1910</option>
    <option value="1909"<?php echo $birthdayYear == '1909' ? 'selected="selected"' : ''; ?>>1909</option>
    <option value="1908"<?php echo $birthdayYear == '1908' ? 'selected="selected"' : ''; ?>>1908</option>
    <option value="1907"<?php echo $birthdayYear == '1907' ? 'selected="selected"' : ''; ?>>1907</option>
    <option value="1906"<?php echo $birthdayYear == '1906' ? 'selected="selected"' : ''; ?>>1906</option>
    <option value="1905"<?php echo $birthdayYear == '1905' ? 'selected="selected"' : ''; ?>>1905</option>
    <option value="1904"<?php echo $birthdayYear == '1904' ? 'selected="selected"' : ''; ?>>1904</option>
    <option value="1903"<?php echo $birthdayYear == '1903' ? 'selected="selected"' : ''; ?>>1903</option>
    <option value="1902"<?php echo $birthdayYear == '1902' ? 'selected="selected"' : ''; ?>>1902</option>
    <option value="1901"<?php echo $birthdayYear == '1901' ? 'selected="selected"' : ''; ?>>1901</option>
    <option value="1900"<?php echo $birthdayYear == '1900' ? 'selected="selected"' : ''; ?>>1900</option>
</select>

如果它不是更高效，那么它肯定更具可读性和可重用性，这一点要重要得多。

<select name="birthdayYear" >
    <option value="0000">Year:</option>
    <?php
        for(var $x = year(); $x >= 1900; $x--) {
            var $selected = "";
            if($x == $birthdayYear) {
                $selected = " selected = 'selected'";
            }
            echo("<option value="$x"$selected>$x</option>");
        }
    ?>
</select>

简而言之，我的头发是一只鸟。

基本上，您将：

自行处理CCD_ 1专线
然后，有一个从2011到1900的for()循环

循环可能看起来有点像这样：

for ($year=2011 ; $year>=1900 ; $year--) {
    echo '<option value="' . $year . '"';
    if ($year == $birthdayYear) {
        echo 'selected="selected"';
    }
    echo '>' . $year . '</option>' . PHP_EOL;
}

当然，2011年份可能不应该被硬编码——看看date()，了解获取当前年份的可能方法。

<select name="birthdayYear" >
    <option value="0000"<?php echo $birthdayYear == '0000' ? 'selected="selected"' : ''; ?>>Year:</option>
<?php
for($i=date('Y'); $i>1899; $i--) {
    $selected = '';
    if ($birthdayYear == $i) $selected = ' selected="selected"';
    print('<option value="'.$i.'"'.$selected.'>'.$i.'</option>'."n");
}
?>
</select>

而且，一个循环会比一个接一个地列出它们更有效吗？

我认为你不必担心效率。使用一个环看起来更干净，我认为它会更容易维护。

for ($x=(int)date("Y"); $x>=1900; $x=$x--) {
    echo "<option value="", $x, """, ($birthdayYear==$x) ? " selected="selected"" : "", ">", $x, "</option>"
}

这还有额外的好处，你不必每年都更新它。

试试这个：

<select name="birthdayYear" >
<?php
if($year == '0000') {
    echo '<option value="0000" selected="selected">0000</option>';
} else {
    echo '<option value="0000">0000</option>';
}
for($year = intval(date('Y')); $year > 1900; $year --) {
    if($year == $birthdayYear) {
        echo '<option value="'.$year.'" selected="selected">'.$year.'</option>';
    } else {
        echo '<option value="'.$year.'">'.$year.'</option>';
    }
}
?>
</select>

首先，输出"0000"选项。它不遵循模式，因此不应包含在循环中：

<option value="0000"<?php echo $birthdayYear == '0000' ? 'selected="selected"' : ''; ?>>Year:</option>

接下来，创建一个循环并输出选项的每个部分。我从date('Y')(当前年份(开始，而不是硬编码的"2011"，因此您的脚本不需要每年更新。

for ( $i = date('Y'); $i >= 1900; $i-- ) {
    echo "<option value="$i"";
    echo $birthdayYear == $i ? 'selected="selected"' : '';
    echo ">$i</option>";
}

这三个echo语句可以合并为一个。为了清晰起见，我把它们分别放在不同的线上。

1900至少和2011一样具有任意性。我们可以制作一个从当前年份起仅跨越100年的版本。

<?php $selectedYear = $_REQUEST['birthdayYear'] ?>
<select id="birthdayYear">
<option value="0">Year:</option>
<?php $currYear = date('Y') ?>
<?php for ($i=0; $i<100; ++$i) : ?>
<?php $displayYear = $currYear-$i ?>
<option value="<?= $displayYear ?>"<?= ($displayYear == $selectedYear ? 'selected="selected"' : '') ?>><?= $displayYear ?></option>
<?php endfor; ?>
</select>

要准确地回到1900，只需将for条件更改为112即可。

请循环。这与其说是代码效率的问题(在这个级别上，这根本不重要(，不如说是开发人员效率的问题：循环看起来更容易，它不会强迫读者滚动或折叠，而且它减少了打字错误引入细微错误的可能性(有了循环，它们要么都错了，要么都正确(。

老实说，任何以这种规则模式包含两个以上条目的下拉列表都会让我抽搐并找到for关键字。他们中的一百个几乎要尴尬了。

<select name="birthday">
<option value="0">-</option>
<?php
    for($i=1990; $i<=2013; $i++) { ?>
<option value="<?php echo $i; ?>">
<?php echo $i; ?>

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