Javascript代码 去除一段string中的所有空行和空白行，内有javascript的trim实现

代码如下，仔细看能看懂，用了一点RE的内容。js中，用//括起来的字符串表示是一个RE字符串。

    function updateStuffs() {
        var response;
        if (request.readyState == 4) {
            if (request.status == 200) {
                response = request.responseText;
                var content_array = response.split("==== DELIMITER ====");
                var peselect = document.getElementById("peselectid");
                var prjselect = document.getElementById("prjselectid");
                var masterqselect = document.getElementById("masterqselectid");
               
                var ls = /^\s*/;  // Leading space regular expression
                var ts = /\s*$/;  // Trailing space regular expression

                // Break the response into lines
                var lines = content_array[0].split("\n");
                var peselect_result = "";
                // Loop through the lines
                for(var i = 0; i < lines.length; i++) {
                    var line = lines[i];
                    if (line.length == 0) continue;  // Skip empty lines
                    line = line.replace(ls, "").replace(ts, "");
                    if (line.length == 0) continue;  // Skip space filling lines
                    peselect_result += line + "\n";
                }

                // Break the response into lines
                lines = content_array[1].split("\n");
                var prjselect_result = "";
                // Loop through the lines
                for(var i = 0; i < lines.length; i++) {
                    var line = lines[i];
                    if (line.length == 0) continue;  // Skip empty lines
                    line = line.replace(ls, "").replace(ts, "");
                    if (line.length == 0) continue;  // Skip space filling lines
                    prjselect_result += line + "\n";
                }
               
                // Break the response into lines
                lines = content_array[1].split("\n");
                var masterq_select_result = "";
                // Loop through the lines
                for(var i = 0; i < lines.length; i++) {
                    var line = lines[i];
                    if (line.length == 0) continue;  // Skip empty lines
                    line = line.replace(ls, "").replace(ts, "");
                    if (line.length == 0) continue;  // Skip space filling lines
                    masterq_select_result += line + "\n";
                }
               
                peselect.innerHTML = "<select name='pe_name' class='listselect'>" + peselect_result + "</select>";
                prjselect.innerHTML = "<select name='project' class='listselect'>" + prjselect_result + "</select>";
                masterqselect.innerHTML = "<select name='master_queue' class='listselect'>" + masterq_select_result + "</select>";
            } else if (request.status == 404) {
                alert("<bean:message key='error.ajax.urlnotexist'/>");
            } else {
                alert("<bean:message key='error.ajax.errorcode'/>" + request.status);
            }
        }
    }