javascript - listbox does not pass string to google script -

when select user listbox, onchange() event triggers function. should pass string function. code finds user's password , returns comparison. following code works fine if hard code user value, not when select listbox.

function addclients(clients){   $('#customer').empty();    $('#customer').append('<option> ---- choose user ----</option>');   (var in clients) {     $('#customer').append('<option>'+clients[i]+'</option>');     $('#customer').trigger("chosen:updated");    } }  

getval function:

function getval(sel){     var usrpass = google.script.run.getuserpass(sel.value);     alert(usrpass); } 

the function in code.gs follows

function getuserpass(userval){  var usrpass = "";  var doc = spreadsheetapp.openbyid("spreadsheet id");  var sheet = doc.getactivesheet();  var data = sheet.getrange(3, 3, sheet.getlastrow(),5).getvalues();;   for(n=0;n<data.length;++n){  // iterate row row , examine data in column  if(data[n][0].tostring().match(userval)==userval){ usrpass = data[n][4]};  }  return usrpass; } 

why return value come undefined rather password.

if hardcode username in function , run function, return value value in fifth column.

try structuring code this:

<script>   function onsuccess(returnval) {     alert('success! ' + returnval);   };    function getval(sel){      var selectvalue = sel.value;     console.log('selectvalue: ' + selectvalue);      google.script.run       .withsuccesshandler(onsuccess)       .getuserpass(sel.value);   };  </script> 

you can iterate through object see in it, debugging test.

for (var propertyval in sel) {   console.log('this property: ' + propertyval);   console.log('this value: ' + sel[propertyval]); }; 

and see in object.