Sending confidential information using JavaScript when calling a web service

Question

I have an ERP system where I have build some web services for it. And for security reasons the consumer of the web service must send a master login username and password (set at my ERP application) in addition to other parameters. for example to call a web service to retrieve the annual salary for an employee the consumer calls the web service using the following URL:-

/jw/web/json/hr/getsalary/byid?master_username=superadmin&password_hash=9449B5ABCFA9AFDA36B801351ED3DF66&employeeid=A200121

Now i have downloaded a free and simple document management system, and to be able to call the above web service from the free software i can only do so using javaScript since i am not the owner of the software, but since i am sending the master_username and password_hash as part of the call then it is not be secure to do this using javaScrpt .

so my question is what other methods (other than master login username and password)i can use to make the web service call secure using javaScript; So the web service should be done using javaScript and should be secure?. Thanks in advance for any help. BR

:::Updated::: The javaScript look something similar to:-

<script type="text/javascript">
$(function() {
$.getJSON("https://MyERPsystem.com/jw/web/json/hr/getsalary/byid?master_username=superadmin&password_hash=9449B5ABCFA9AFDA36B801351ED3DF66&employeeid=A200121",
  {
//code goes here
  },
  function(data) {
    $.each(data.items, function(i,item){
//code goes here
    });
});
}) </script>

Answer 1

you can use an SSL connection which is by default encrypted.

ps i'm not sure i understand why you can't authenticate users normally and then accept queries only for users in the authenticated SESSION.