Onclick does not work on IOs 7

I made a javascript that calls a map of google maps every time I click it it opens a lightbox and then puts the map in.

The problem I've already tested on Android (Chrome), Windows Phone (IE), and PC (chrome and firefox).

All of them are working, except in IOs, I've tested chrome and safari and nothing.

<button class="btncontato" onclick="AbrirPopup();setavalores(
'-23.5664359', 
'-46.7120167', 
'Avenida Afrânio Peixoto, 137 – Butantã', 
'05507-000', 
'SÃO PAULO – Capital',
'Fone: 11 3543-0100'
);
initialize('mapLeft')"> Ver Mapa </button>

I have tried to put only onclick="alert" and it worked, however when I try to open the popup it does not open.

function AbrirPopup() {
alert('entrou na função');
document.getElementById('light').style.display= 'block';
document.getElementById('fade').style.display='block';      
}

Can anyone help me how can I solve it? I did not want to install Jquery, because the whole project was done without and I think it would be unfeasible to put just to solve a function.

Thank you