​

  function splitString(str, index) {

    var delim = /\s|[,\.]/; // Put any other character you consider

                            // a non-word char in the brackets

    var ch;

    var i,n;

    for (i = index;

         i <= 40 && !delim.test(str.charAt(i));

         --i) {

      // No body

    }

    if (i < 0) {

      // No break before, split word in middle

      n = index;

    }else n = i;

    if(n<str.length) return str.substring(0,n)+'...';

    else return str;

  }

​

  var str, splitPoint;

  str = "Ich bin ein Blindtext oder der nichts kann";  splitPoint = splitString(str, 25);

  display(splitPoint);

​

  function display(msg) {

    var aaa = document.GetElementsByTagName("<p>").innerHTML = (msg);

  }