function blobDownload(value, fileName, type){
    let blob = new Blob([value], {type: type})
    let downloadElement = document.createElement('a')
    downloadElement.href = window.URL.createObjectURL(blob)
    downloadElement.setAttribute('download', fileName)
    document.body.appendChild(downloadElement)
    downloadElement.click()
    document.body.removeChild(downloadElement)
    window.URL.revokeObjectURL(downloadElement.href) // 释放blob对象
}