1. The difference between urlencode and rawurlencode
<?php test('https://tieba.baidu.com/f?kw=2&fr=wwwt'); test(':/?= &#'); test('测试'); function test($s) { echo "<b>urlencode('$s')</b> = [<b>"; var_dump(urlencode($s)); echo "</b>]<br/>"; echo "<b>rawurlencode('$s')</b> = [<b>"; var_dump(rawurlencode($s)); echo "</b>]<br/>"; } //运行结果 urlencode('https://tieba.baidu.com/f?kw=2&fr=wwwt') = [ D:\software\wamp\www\linux\webApi\test.php:9:string 'https%3A%2F%2Ftieba.baidu.com%2Ff%3Fkw%3D2%26fr%3Dwwwt' (length=54) ] rawurlencode('https://tieba.baidu.com/f?kw=2&fr=wwwt') = [ D:\software\wamp\www\linux\webApi\test.php:12:string 'https%3A%2F%2Ftieba.baidu.com%2Ff%3Fkw%3D2%26fr%3Dwwwt' (length=54) ] urlencode(':/?= &#') = [ D:\software\wamp\www\linux\webApi\test.php:9:string '%3A%2F%3F%3D+%26%23' (length=19) ] rawurlencode(':/?= &#') = [ D:\software\wamp\www\linux\webApi\test.php:12:string '%3A%2F%3F%3D%20%26%23' (length=21) ] urlencode('测试') = [ D:\software\wamp\www\linux\webApi\test.php:9:string '%E6%B5%8B%E8%AF%95' (length=18) ] rawurlencode('测试') = [ D:\software\wamp\www\linux\webApi\test.php:12:string '%E6%B5%8B%E8%AF%95' (length=18) ]
As can be seen from the above execution results, the results of the two methods urlencode and rawurlencode are the same when processing letters, numbers, special symbols, and Chinese. , the only difference is the processing of spaces, urlencode is processed as " ", rawurlencode is processed as " "
2. Function strip_tags: remove HTML and PHP tags
Note: This function can remove any HTML and PHP tag strings contained in the string. If the HTML and PHP tags of the string are originally wrong, for example, the greater than symbol is missing, an error will also be returned. This function has the same function as fgetss(). fgetss reads the file from the file and removes the html and php tags.
<?php echo strip_tags("Hello <b>world!</b>");
Run results
Hello world!
3. Function htmlspecialchars, convert special characters into HTML format
htmlspecialchars() function converts predefined characters Convert to HTML entities.
The predefined characters are:
& (ampersand) becomes &
" (double quotation mark) becomes "
' (single quotation mark) becomes '
< (less than) becomes <
> (greater than) becomes>
##
<?php echo htmlspecialchars("This is some <b>bold</b> text.&");
This is some <b>bold</b> text.&
<?php echo htmlentities("<? W3S?h????>");
<? W3S?h????>
Single quotation mark (')
Double quotation mark (")
Backslash (\)
NULL
<?php echo addslashes('Shanghai is the "biggest" city in China.');
Shanghai is the \"biggest\" city in China.
<?php echo stripslashes("Who\'s Bill Gates?");
Who's Bill Gates?
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