删除开头和结尾的特殊字符

试试这个:

preg_replace( '/^'W*(.*?)'W*$/', '$1', $string )
/* -----------------------------------------------------------------------------------
  ^                        the beginning of the string
    'W*                    non-word characters (all but a-z, A-Z, 0- 9, _) (0 or more times (matching the most amount possible))
    (                      group and capture to '1:
      .*?                  any character except 'n (0 or more times(matching the least amount possible))
    )                      end of '1
    'W*                    non-word characters (all but a-z, A-Z, 0-9, _) (0 or more times (matching the most amount possible))
  $                        before an optional 'n, and the end of the string
------------------------------------------------------------------------------------- */

PHP的trim函数可能会帮助您，使用第二个参数传递您想要删除的字符。问题是，你必须列出你想要删除的字符，而不是你想要保留的字符。

trim($string,$remove);

其中$remove包含您希望从开始和结束处删除的字符

我们创建了一个函数并检查javascript的特殊字符

 var string  = "@@@@@M@@@@U###@@";
 var output = filterSpecialChar(string);
 console.log(output); //M@@@@U
 function filterSpecialChar(string){
     var arrayString = string.split("");
     var count = arrayString.length/2;
     var check_float =  Number(count) === count && count % 1 !== 0;
     var format = /[!@#$%^&*()_+'-='[']{};':"''|,.<>'/?]+/;
     if(check_float == true){
        var start_length = parseInt(count)+1;
        var end_length = parseInt(count);
     }else{
        var start_length = parseInt(count);
        var end_length = parseInt(count);
     }
        for(var i=0;i<parseInt(arrayString.length);i++){
        if(format.test(arrayString[i])){
          arrayString[i] = null; 
        }else{
            break;
        }   
    }
    for(var i=arrayString.length-1;i>0;i--){
        if(format.test(arrayString[i])){
          arrayString[i] = null; 
        }else{
            break;
        }   
    }
   var arrayString = arrayString.filter(function(data){return data != null});
   return arrayString.join('');
 }  

尝试使用锚点:

^[^a-zA-Z0-9_ %'[']'.'(')%&-]|[^a-zA-Z0-9_ %'[']'.'(')%&-]$