js file base64

function readFileAsBase64(file) {
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        reader.onload = () => resolve(reader.result);
        reader.onerror = reject;
        reader.readAsDataURL(file);
    });
}

// 使用示例
const fileInput = document.querySelector('input[type="file"]');
fileInput.addEventListener('change', async (event) => {
    const file = event.target.files[0];
    try {
        const base64 = await readFileAsBase64(file);
        console.log(base64);
    } catch (error) {
        console.error('Error reading file:', error);
    }
});

function base64ToBlob(base64, mimeType) {
    const byteCharacters = atob(base64.split(',')[1]);
    const byteArrays = [];
    for (let i = 0; i < byteCharacters.length; i++) {
        byteArrays.push(byteCharacters.charCodeAt(i));
    }
    return new Blob([new Uint8Array(byteArrays)], { type: mimeType });
}

// 使用示例
const base64String = 'data:text/javascript;base64,...'; // 替换为实际的 Base64 字符串
const blob = base64ToBlob(base64String, 'text/javascript');
const url = URL.createObjectURL(blob);
const script = document.createElement('script');
script.src = url;
document.head.appendChild(script);