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### ElementUI version
<!-- 1.0.0-rc.2 -->

### OS/Browers version
<!-- macOS/Chrome 53 -->

### Vue version
<!-- 2.0.0-rc.4 -->

### Reproduction Link
<!-- A minimal JSBin, JSFiddle, Codepen, or a GitHub repository that can reproduce the bug. -->
<!-- https://codepen.io/anon/pen/ozYpNA -->
<!-- https://jsfiddle.net/gmve9d3p/ -->

### Steps to reproduce

### What is Expected?

### What is actually happening?
