## 方法（全局指令）
```
Vue.directive('drag-modal', (el, bindings, vnode) => {
Vue.nextTick(() => {
let { visible, destroyOnClose } = vnode.componentInstance;
// 防止未定義 destroyOnClose 關閉彈窗時dom未被銷毀，指令被重復調用
if (!visible) return;
let modal = el.getElementsByClassName('ant-modal')[0];
let header = el.getElementsByClassName('ant-modal-header')[0];
let left = 0;
let top = 0;
// 未定義 destroyOnClose 時，dom未被銷毀，關閉彈窗再次打開，彈窗會停留在上一次拖動的位置
if (!destroyOnClose) {
left = modal.left || 0;
top = modal.top || 0;
}
// top 初始值為 offsetTop
top = top || modal.offsetTop;
header.onmousedown = e => {
let startX = e.clientX;
let startY = e.clientY;
header.left = header.offsetLeft;
header.top = header.offsetTop;
el.onmousemove = event => {
let endX = event.clientX;
let endY = event.clientY;
modal.left = header.left + (endX - startX) + left;
modal.top = header.top + (endY - startY) + top;
modal.style.left = modal.left + 'px';
modal.style.top = modal.top + 'px';
};
el.onmouseup = () => {
left = modal.left;
top = modal.top;
el.onmousemove = null;
el.onmouseup = null;
header.releaseCapture && header.releaseCapture();
};
header.setCapture && header.setCapture();
};
});
});
```
## 使用 （v-drag-modal）
`v-drag-modal`
