class svgChart {
      constructor(element, data, colors=[], step) {
        this.element = element
        this.data = data
        this.colors = colors
        this.step = step
      }
      init() {
        let maxH = Math.max.apply(null, this.data)
        let svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg')
        svg.setAttribute('xmlns', 'http://www.w3.org/2000/svg')
        svg.setAttribute('viewBox', `0 0 ${this.data.length * this.step} ${maxH}`)
        svg.setAttribute('width', this.data.length * this.step)
        svg.setAttribute('height', maxH)
        this.data.forEach((element, index) => {
          let child = document.createElementNS('http://www.w3.org/2000/svg', 'rect')
          child.setAttribute('width', `${this.step}px`)
          child.setAttribute('height', `${element}px`)
          child.setAttribute('x', index * this.step)
          child.setAttribute('y', `${maxH - element}px`)
          child.setAttribute('fill', this.colors[index])
          svg.appendChild(child)
        })
        this.element.appendChild(svg)
      }
    }