Ios External Navigation Problem

I want to add Itunes store link, fb,twitter etc… links to my ionic ios app. but its not working

I added in config.xml

and i am opening the page like this

{
text: ‘Purchase’,
type: ‘button-positive’,
onTap: function(e) {
window.open(‘https://itunes.apple.com/us/app/smoocing-pro/id1097485400’, ‘_system’, ‘location=yes’);
return ‘ok button’
}

I tried many ways ,Please Help me