js 实现左右两个div根据高度自使用 高度一致

<div className="stateList" style={{this.state.firstWidth,marginRight:this.state.right,marginBottom: '-5000px',paddingBottom:' 5000px'}} id='leftSides' >

var left = document.getElementById('leftSides');
		if (left.offsetHeight >= val) {
			this.setState({
				height:left.offsetHeight + 'px'
			})
		} else {
			left.style.height = val + 'px';
		}
		this.setState({
			rightHeight:val
		})