<core:View xmlns:core="sap.ui.core" xmlns:mvc="sap.ui.core.mvc" xmlns="sap.m" xmlns:l="sap.ui.layout" xmlns:f="sap.ui.layout.form"
        controllerName="view.login" xmlns:html="http://www.w3.org/1999/xhtml" >
    <Page title="WEBAPP">
        <content>

        <FlexBox
          alignItems="Center"
          justifyContent="Center">
          <items>
            <Image src="general/img/logo.png" width="{/widthL}"/>
          </items>
        </FlexBox>

        <FlexBox
          alignItems="Center"
          justifyContent="Center">
          <items>

            <l:Grid
            defaultSpan="L12 M12 S12"
            width="auto">
            <l:content>
              <f:Form id="loginForm"
                minWidth="1024"
                maxContainerCols="2"
                editable="true">
                <f:title>
                  <core:Title text="" />
                </f:title>
                <f:layout>
                  <f:ResponsiveGridLayout
                    labelSpanL="3"
                    labelSpanM="3"
                    emptySpanL="4"
                    emptySpanM="4"
                    columnsL="1"
                    columnsM="1" />
                </f:layout>
                <f:formContainers>
                  <f:FormContainer>
                    <f:formElements>
                      <f:FormElement label="Username">
                        <f:fields>
                          <Input id="id_inputUsername" />
                        </f:fields>
                      </f:FormElement>
                      <f:FormElement label="Password">
                        <f:fields>
                          <Input id="id_inputPassword" type="Password" />
                        </f:fields>
                      </f:FormElement>
                    </f:formElements>
                  </f:FormContainer>
                </f:formContainers>
              </f:Form>
            </l:content>
          </l:Grid>


          </items>
        </FlexBox>


        </content>
        <footer>
        <Bar>
         <contentRight>
            <Button id="idButtonLogin" text="Login" type="Emphasized" visible="true" press="handleFooterBarButtonPress" icon="sap-icon://accept" />
         </contentRight>
        </Bar>
        </footer>
    </Page>
</core:View>

<Input id="id_inputPassword"
  type="Password"
  change="onPasswordChange" />

...

<Button id="idButtonLogin"
  text="Login"
  type="Emphasized"
  visible="true"
  press="handleFooterBarButtonPress"
  icon="sap-icon://accept" />

onPasswordChange : function(oEvent) {
  this.getView().byId("idButtonLogin").firePress();
},

handleFooterBarButtonPress : function(oEvent) {
  jQuery.sap.require("sap.m.MessageToast");
  sap.m.MessageToast.show("Login!");
}

$('#id_inputPassword').on('keydown',function(e){
    e.stopPropagation();
    if (e.keyCode == 13)
    {
        $('#formLogin').submit();
    }
});

sap.ui.getCore().byId("inputUserName").attachBrowserEvent('keyup', function(e) {
        if (e.which == 13 || e.keyCode == 13) {
            var userName = sap.ui.getCore().byId("inputUserName").getValue();
            var password = sap.ui.getCore().byId("inputPassword").getValue();
            if (userName.length == 0) {
                sap.ui.getCore().byId('inputUserName').setValueState('Error');
                sap.ui.getCore().byId('inputUserName').focus();
            } else if (password.length == 0) {
                sap.ui.getCore().byId('inputPassword').setValueState('Error');
                sap.ui.getCore().byId('inputPassword').focus();
            } else if (userName.length > 0 && password.length > 0) {
                    //YOUR LOGIC
            }
        }
    });


//another way by using sap's default saponenter function
sap.ui.getCore().byId("inputPassword").onsapenter = function(e) {
         var userName = sap.ui.getCore().byId("inputUserName").getValue();
         var password = sap.ui.getCore().byId("inputPassword").getValue();
         if (userName.length == 0) {
             sap.ui.getCore().byId('inputUserName').setValueState('Error');
             sap.ui.getCore().byId('inputUserName').focus();
         } else if (password.length == 0) {
             sap.ui.getCore().byId('inputPassword').setValueState('Error');
             sap.ui.getCore().byId('inputPassword').focus();
         } else if (userName.length > 0 && password.length > 0) {
             //your logic
         }
    }

$('#idButtonLogin').bind('keydown', function(e) {
    if (e.keyCode == 13) {
        // Here you can call the function
    }
});