为什么你给我的下列代码提示我 return CryptoJSSHA256getTextblock chain;这句话有问题 缺少getTEXT定义怎么修改extends layoutblock content container-fluid h1 #__Blockchain rowrow-horizon - var blocks = - for var i =

在给出的代码中，确实缺少了getText函数的定义，导致了提示错误。要修复这个问题，你需要在代码中添加getText函数的定义。在给出的代码中，getText函数的定义和实现已经在脚本标签中给出了，所以你只需要将这部分代码移动到blockchain.js文件中即可。

修改后的blockchain.js文件如下所示：

var difficulty = 5;        // number of zeros required at front of hash
var maximumNonce = 50000000; // limit the nonce to this so we don't mine too long

// NOTE: Because there are 16 possible characters in a hex value, each time you increment
// the difficulty by one you make the puzzle 16 times harder. In my testing, a difficulty
// of 6 requires a maximumNonce well over 500,000,000.

/////////////////////////
// global variable setup
/////////////////////////
var pattern = '';
for (var x = 0; x < difficulty; x++) {
  pattern += '0';
}

/////////////////////////
// functions
/////////////////////////

function sha256(block, chain) {
  // calculate a SHA256 hash of the contents of the block
  return CryptoJS.SHA256(getText(block, chain));
}

function getText(block, chain) {
  return $('#block'+block+'chain'+chain+'number').val() +
         $('#block'+block+'chain'+chain+'nonce').val() +
         $('#block'+block+'chain'+chain+'data').val() +
         $('#block'+block+'chain'+chain+'previous').val();
}

function updateState(block, chain) {
  // set the well background red or green for this block
  if ($('#block' + block + 'chain' + chain + 'hash').val().substr(0, difficulty) === pattern) {
    $('#block' + block + 'chain' + chain + 'well').removeClass('well-error').addClass('well-success');
  }
  else {
    $('#block' + block + 'chain' + chain + 'well').removeClass('well-success').addClass('well-error');
  }
}

function updateHash(block, chain) {
  // update the SHA256 hash value for this block
  $('#block' + block + 'chain' + chain + 'hash').val(sha256(block, chain));
  updateState(block, chain);
}

function updateChain(block, chain) {
  // update all blocks walking the chain from this block to the end
  for (var x = block; x <= 5; x++) {
    if (x > 1) {
      $('#block' + x + 'chain' + chain + 'previous').val($('#block' + (x - 1).toString() + 'chain' + chain + 'hash').val());
    }
    updateHash(x, chain);
  }
}

function mine(block, chain, isChain) {
  console.log("Here I start!");
  var t0 = performance.now();
  for (var x = 0; x <= maximumNonce; x++) {
    $('#block' + block + 'chain' + chain + 'nonce').val(x);
    $('#block' + block + 'chain' + chain + 'hash').val(sha256(block, chain));
    if ($('#block' + block + 'chain' + chain + 'hash').val().substr(0, difficulty) === pattern) {
      if (isChain) {
        updateChain(block, chain);
      }
      else {
        updateState(block, chain);
      }
      break;
    }
  }
  var t1 = performance.now();
  console.log("Call to someFunction took " + Math.floor(t1 - t0) + " milliseconds.");
}

// Generate block data
for (var i = 1; i <= 1000; i++) {
  $('#block' + i.toString() + 'chain1data').val(i);
}

// Mine 300 times and calculate average time
var totalTime = 0;
for (var j = 1; j <= 300; j++) {
  var t0 = performance.now();
  for (var k = 1; k <= 1000; k++) {
    mine(k, 1, false);
  }
  var t1 = performance.now();
  totalTime += (t1 - t0);
}

var averageTime = totalTime / 300;
console.log("Average time: " + averageTime + " milliseconds.");

在这个修改后的代码中，getText函数的定义已经添加到了blockchain.js文件中，可以正常使用了