js把預定義的html字符串轉換為 HTML 實體 htmlspecialchars 輸出html實體內容包括標簽，而不自動轉義標簽，只顯示內容，類似php的htmlspecialchars

一、html字符串轉換為 HTML 實體 htmlspecialchars

function htmlspecialchars(str){           
          str = str.replace(/&/g, '&');  
          str = str.replace(/</g, '&lt;');  
          str = str.replace(/>/g, '&gt;');  
          str = str.replace(/"/g, '&quot;');  
          str = str.replace(/'/g, '&#039;');  
          return str;  
}  
        
//這個版本多轉換了一些內容  
function htmlspecialchars(str) {       
              var s = "";  
              if (str.length == 0) return "";  
              for   (var i=0; i<str.length; i++)  
              {  
                  switch (str.substr(i,1))  
                  {  
                      case "<": s += "&lt;"; break;  
                      case ">": s += "&gt;"; break;  
                      case "&": s += "&amp;"; break;  
                      case " ":  
                          if(str.substr(i + 1, 1) == " "){  
                              s += " &nbsp;";  
                              i++;  
                          } else s += " ";  
                          break;  
                      case "\"": s += "&quot;"; break;  
                      case "\n": s += "<br>"; break;  
                      default: s += str.substr(i,1); break;  
                  }  
              }  
              return s;  
          }

 

二、HTML實體 轉換為 html字符串 htmlspecialchars_decode

    將上面的htmlspecialchars中的匹配反過來如：

    function htmlspecialchars_decode(str){           
              str = str.replace(/&amp;/g, '&');
              str = str.replace(/&lt;/g, '<');
              str = str.replace(/&gt;/g, '>');
              str = str.replace(/&quot;/g, "''");  
              str = str.replace(/&#039;/g, "'");  
              return str;  
    }