function isEmptyStr(testStr) {
        var reg1;
        var outVal=true;

        reg1= "^ *$";
        re = new RegExp(reg1);
        if( !re.test(testStr) )
            outVal = false;
        return(outVal);
    }

        /* Strip whitespace from the beginning and end of a string */
        if (typeof String.prototype.trim == "undefined") {
            String.prototype.trim = function () {
                var s = this.replace(/^\s*/, "");
                return s.replace(/\s*$/, "");
            }
        }

    if( txt.trim()=='' ) {
         alert('empty text!!');
    }