js判断输入框不能全是空格

     var sno =  $('#sno').val();   var sname = $('#sname').val(); while(sno.lastIndexOf(" ")>=0 || sname.lastIndexOf(" ")>=0){ sno = sno.replace(" ",""); sname = sname.replace(" ","");    }    if(sno.length == 0 || sname.length == 0){     alert("不能全是空格！");     $('#dd').dialog('close');    $('#dg').datagrid('reload');    }else{}