Vue 2 removes former event listeners

I’m currently trying VueJS 2 and noticed a change when using it on existing DOM Indeed everytime VueJS is initialised it will do something on existing DOM and will remove events previously binded outside of VueJS.

// We bind an event
document.querySelector('#demo').addEventListener('click', function () {
    alert("i'm a button")
})

// and it's lost when Vue is binded
new Vue({
    el: '#vuejs'
})

JSFiddle

This same example works fine with VueJS1. I don’t have enough understanding of Vue core to understand what changed between the two version of the compiler.js that would explain this change.

[oppianmatt]

what if you’re in the process of trying to migrate to vue, but you have some legacy parts in jquery trying to move to vue now means an all or nothing approach this bit me trying out my first vue component amongst my legacy components

so what you’re saying is that I have to move all of them to vuejs and there is no way to intermingle?

[Art4]

I’m new to Vue.js and I stumbled upon this issue in a project where we want to migrate from jquery to Vue incrementally. After a week of try and error I finally found this issue on Github. So I put the Vue code above the old jquery code and finally everything works. 🎉

This behavior should be definitely in the docs, maybe somewhere at the beginning.