array.map 和 sendAsBinary的兼容实现

code_snippet.js

/**
 * http://javascript0.org/wiki/Portable_sendAsBinary 
 * portable sendAsBinary 
 */

XMLHttpRequest.prototype.sendAsBinary = function(datastr) {
    function byteValue(x) {
        return x.charCodeAt(0) & 0xff;
    }
    var ords = Array.prototype.map.call(datastr, byteValue);
    var ui8a = new Uint8Array(ords);
    this.send(ui8a.buffer);
}


/**
 *  http://www.tutorialspoint.com/javascript/array_map.htm
 *  Array.map(callback[,thisObj])  
 *  This method is a JavaScript extension to the ECMA-262 standard 
 *  Compatibility 
 */

if (!Array.prototype.map)
{
  Array.prototype.map = function(fun /*, thisp*/)
  {
    var len = this.length;
    if (typeof fun != "function")
      throw new TypeError();

    var res = new Array(len);
    var thisp = arguments[1];
    for (var i = 0; i < len; i++)
    {
      if (i in this)
        res[i] = fun.call(thisp, this[i], i, this);
    }

    return res;
  };
}