PHP 語言中,echo 是一個(gè)最常用的內(nèi)置函數(shù)。它的作用,就是輸出一個(gè)或者多個(gè)字符串。
用 echo 輸出一個(gè)字符串在 PHP 語法中,我們已經(jīng)舉過一個(gè)簡(jiǎn)單的 echo 的示例,如下:
<html><body> <?phpecho "Blabla.cn"?> </body></html>
返回的 HTML 結(jié)果是:
<html><body>Blabla.cn</body></html>
我們將這個(gè)例子再寫復(fù)雜一點(diǎn),加上 HTML 標(biāo)記,如下:
<html><body><?phpecho "<h1>Blabla.cn</h1>"?></body></html>
返回的 HTML 結(jié)果是:
<html><body><h1>Blabla.cn</h1></body></html>用 echo 輸出多個(gè)字符串
echo 也可以輸出多個(gè)字符串,用逗號(hào) DE<, DE<分隔。示例如下:
<html><body><?phpecho "woyouxian.net", " and ","blabla.cn"?></body></html>
返回的顯示結(jié)果是:
woyouxian.net and blabla.cn用 echo 輸出變量的值
echo 還可以輸出變量的值。示例如下:
<html><body><?php$a = "blabla.cn";echo $a?></body></html>
上面代碼中,$a 是一個(gè)變量,$a 的值是 "blabla.cn",用 echo 輸出 $a 的值。
顯示的結(jié)果是:
blabla.cn
再比如,輸出兩個(gè)變量的值:
<html><body><?php$a = "woyouxian.net "; $b = "blabla.cn";echo $a,$b?></body></html>
返回的顯示結(jié)果是:
woyouxian.net blabla.cnecho 的字符串參數(shù)里含有變量
如果 echo 的字符串參數(shù)里含有變量,有兩種情況:第一種是字符串參數(shù)用雙引號(hào),echo 輸出變量的值;第二種是字符串參數(shù)使用單引號(hào),則輸出變量名。
字符串采用雙引號(hào)的示例如下:
$a = "just in case"; echo "take the gun,$a";
返回的結(jié)果是:
take the gun,just in case
上例中,字符串采用雙引號(hào),在字符串里的變量輸出變量的值。
再看字符串用單引號(hào)的情況。示例如下:
$a = "just in case";echo 'take the gun,$a';
在字符串使用單引號(hào)的情況下,返回的結(jié)果是輸出變量名稱,而不是變量的值:
take the gun,$a

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