使用struts2+Ajax+jquery驗證用戶名是否已被注冊
748
2024-03-09
echo "asd";//字符串
echo "ads$c";//字符串+變量
echo 'ads$c';//字符串 asd$c $c不是變量
echo "sd"."vs";
echo "sd","vs";
echo $a;
echo $a.$b;
echo $a,$b;
echo $a.$b.$c;
echo $a,$b,$c;
echo "kaskd{$c}asd";
echo "kakskd{$arr['lo']}";
echo "kakskd{$obj->a}";
echo "kaskd".$c."kasd";
echo "kaskd".$arr['lo']."kasd";
echo "kaskd".$obj->a."kasd";
echo "kaskd".func($c)."kasd";
echo "kaksk".($a+1)."dkkasd";
echo $c."jaksd";
echo $c,"jaksd";
//php多行輸出方法
echo <<<END
This uses the "here document" syntax to output
END;
//輸出簡寫
<?php echo $a;?> <?=$a?>
<?php
echo "Hello World";
echo "This spans
multiple lines. The newlines will be
output as well";
echo "This spansnmultiple lines. The newlines will benoutput as well.";
echo "Escaping characters is done "Like this".";
// You can use variables inside of an echo statement
$foo = "foobar";
$bar = "barbaz";
echo "foo is $foo"; // foo is foobar
// You can also use arrays
$baz = array("value" => "foo");
echo "this is {$baz['value']} !"; // this is foo !
// Using single quotes will print the variable name, not the value
echo 'foo is $foo'; // foo is $foo
// If you are not using any other characters, you can just echo variables
echo $foo; // foobar
echo $foo,$bar; // foobarbarbaz
// Some people prefer passing multiple parameters to echo over concatenation.
echo 'This ', 'string ', 'was ', 'made ', 'with multiple parameters.', chr(10);
echo 'This ' . 'string ' . 'was ' . 'made ' . 'with concatenation.' . "n";
echo <<<END
This uses the "here document" syntax to output
multiple lines with $variable interpolation. Note
that the here document terminator must appear on a
line with just a semicolon. no extra whitespace!
END;
// Because echo does not behave like a function, the following code is invalid.
($some_var) ? echo 'true' : echo 'false';
// However, the following examples will work:
($some_var) ? print 'true' : print 'false'; // print is also a construct, but
// it behaves like a function, so
// it may be used in this context.
echo $some_var ? 'true': 'false'; // changing the statement around
?>
以下是官方手冊說明：
Definition and Usage
定義和用法
The echo() function outputs one or more strings.
echo()函數的作用是：輸出一個或多個字符串。
Syntax
語法
echo(strings)
Parameter參數 Description描述
strings Required. One or more strings to be sent to the output
必要參數。指定一個或多個需要被發送到結果中的字符串
Tips and Notes
提示和注意點
Note: The echo() function is not actually a function, so you are not required to use parentheses with it. However, if you want to pass more than one parameter to echo(), using parentheses will generate a parse error.
注意：echo()函數不是一個真正意義上的函數，所以你沒有必要一定去使用它。如果你想把多于一個的參數傳遞給echo()函數，那么使用圓括號“()”將產生錯誤。
Tip: The echo() function is slightly faster than print().
提示：echo()函數相當于print()函數的簡化版本。
Tip: The echo() function has the following shortcut syntax. See example 5.
提示：echo()函數包含下面的簡便寫法。具體見：案例5。
Example 1
案例1
<?php
$str = "Who's Kai Jim?";
echo $str;
echo "<br />";
echo $str."<br />I don't know!";
?>
The output of the code above will be:
上述代碼將輸出下面的結果：
Who's Kai Jim?Who's Kai Jim?I don't know!
Example 2
案例2
<?php
echo "This textspans multiplelines.";
?>
The output of the code above will be:
上述代碼將輸出下面的結果：
This text spans multiple lines.
Example 3
案例3
<?php
echo 'This ','string ','was ','made ','with multiple parameters';
?>
The output of the code above will be:
上述代碼將輸出下面的結果：
This string was made with multiple parameters
Example 4
案例4
Difference of single and double quotes. Single quotes will print the variable name, not the value:
區別單引號(')和雙引號(”)的不同。單引號將輸出變量名，而不是變量的值：
<?php
$color = "red";
echo "Roses are $color";
echo "<br />";
echo 'Roses are $color';
?>
The output of the code above will be:
上述代碼將輸出下面的結果：
Roses are redRoses are $color
Example 5
案例5
Shortcut syntax:
簡寫（捷徑）語法：
<html><body>
<?php
$color = "red";
?><p>Roses are <?=$color?></p></body></html>
