这段代码是如何将字符转为二进制并且去掉大于 255 个以外的字符的的

/**

• Convert a raw string to an array of little-endian words
• Characters >255 have their high-byte silently ignored.
• @param {string} input Raw input string
• @returns {Array<number>} Array of little-endian words */ function rstr2binl(input) { var i var output = [] output[(input.length >> 2) - 1] = undefined for (i = 0; i < output.length; i += 1) { output[i] = 0 } var length8 = input.length * 8 for (i = 0; i < length8; i += 8) { output[i >> 5] |= (input.charCodeAt(i / 8) & 0xff) << i % 32 } return output }