How to filter highlighting illegal characters _php basics

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I'm just doing a test, and if you use a TMD-like string, be sure to note that if the character in the string appears in $startreplacehtml or $endreplacehtml, you need to modify the rules in the following preg_replace
$CheckedMessage = "hello!! He's X's. He.... X... ....     How to Are you M d "; The message to is checked
echo $CheckedMessage. " <br> ";
$CheckedWords =array ("He X's", "TMD")//to filter the illegal characters, if you need to put a single character also filtered, such as: he ererX000 to filter out his, x, you do not need to set the filter character "he X" as long as the set to $ Checkedwords=array ("He", "X", "the");
$StartReplaceHtml = "<u><b><font color= ' #FF0000 ' >";
$EndReplaceHtml = "</font></b></u>";
$CheckOther = true;//Sets the indicator bit, whether a single character is displayed, and if set to true, the following if (Strstr ...) You don't need it.
for ($i =0; $i <count ($CheckedWords); $i + +) {
if (Strstr ($CheckedMessage, $CheckedWords [$i]) {//Here you can remove
$CheckedMessage =eregi_replace ($CheckedWords [$i], $StartReplaceHtml. $CheckedWords [$i]. $EndReplaceHtml, $ Checkedmessage)//If you only filter strings such as "he X" (is a string, not a single character), you can write the sentence directly and set the $checkother to False
}
if ($CheckOther = = True) {
$CharStringLength = strlen ($CheckedWords [$i]);
for ($j =0; $j < $CharStringLength; $j + +) {
$AssumeLength =1;//assumed intercept length
if (Ord ($CheckedWords [$i], $j, $AssumeLength)) (>0xa0) {//If the Chinese character, assuming the length plus a
$AssumeLength + +;
}
$SubstrChar = substr ($CheckedWords [$i], $j, $AssumeLength);
$CheckedMessage =preg_replace ("/<!fon)". $SubstrChar. " /", $StartReplaceHtml. $SubstrChar. $EndReplaceHtml, $CheckedMessage);//replace character, and if the character contains T, the T in <font> will not be replaced. If you need to filter out the characters in the $startreplace or in the $endreplacehtml, you need to modify the rules, otherwise there will be garbled
if ($AssumeLength!=1) {//If the currently intercepted character is Chinese
$j + +;
}

}
}
}
Echo $CheckedMessage;
Just a simple test, hope to help you, I hope you can extrapolate, good luck!

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