Question

一个奇怪的问题。很难用几句话来形容，但我会试试。（我是JavaScript初学者）。

当鼠标悬停在.u标签上时，我希望它能够做某事。所以我有：

var dotUElements = document.getElementsByClassName("u");

for (var ii = 0; ii < dotUElements.length; ii++) {
    dotUElements[ii].onmouseover = createHandler1( dotUElements[ii] );
    dotUElements[ii].onmouseout = createHandler2( dotUElements[ii] );
}

然后添加处理程序：

function createHandler1( myobj ) {
    return (function() {ff1(myobj);});
}

function createHandler2( myobj ) {
    return (function() {ff2(myobj);});
}

我的函数ff1用于鼠标悬停，ff2用于鼠标输出：

function ff1 (myobj) {
    myobj.style.color="red";
    var uChar = myobj.firstChild.nodeValue;
    var uNum =  uChar.charCodeAt(0);
    uName = unicodeTable(uNum);
    var uHex = (uNum).toSring(16);
}

function ff2 (myobj) {
    myobj.style.color="black";
}

问题是最后一行

    var uHex = (uNum).toSring(16);

它会产生错误：

Error: TypeError: uNum.toSring is not a function

如果我只用

替换那一行

(30).toSring(16);

同样的错误。什么是错的任何暗示？我有代码 http://xahlee.info/js/ex/xx_test.html

Answer 1

以下是您的示例的工作演示

function unicodeTable(num) {
  var unicodedata = {
    0x2190: "LEFTWARDS ARROW",
    0x2191: "UPWARDS ARROW",
    0x2192: "RIGHTWARDS ARROW",
    0x2193: "DOWNWARDS ARROW",
  };
  return unicodedata[num];
}

function createHandler1(myobj) {
  return (function() {
    ff1(myobj);
  });
}

function createHandler2(myobj) {
  return (function() {
    ff2(myobj);
  });
}

function ff1(myobj) {
  myobj.style.color = "red"; // test code. so we know it's activated
  var uChar = myobj.firstChild.nodeValue;
  var uNum = uChar.charCodeAt(0);
  uName = unicodeTable(uNum);
  var uHex = (uNum).toString(16);
  alert(uHex);
}

function ff2(myobj) {
  myobj.style.color = "black"; // test code. so we know it's activated
}

var dotUElements = document.getElementsByClassName("u");

for (var ii = 0; ii < dotUElements.length; ii++) {
  dotUElements[ii].onmouseover = createHandler1(dotUElements[ii]);
  dotUElements[ii].onmouseout = createHandler2(dotUElements[ii]);
}

<body>

  <h1>unicode test 3</h1>

  <p>
    <b class="u">←</b>
    <b class="u">→</b>
    <b class="u">↑</b>
    <b class="u">↓</b>
  </p>

  <p>when mouse hover on b.u element, show the unicode name.</p>
</body>

我添加了alert(uHex);来显示值。

如果它不起作用，请告诉我。

奇数事件处理程序错误：num.toString不是函数

1 个答案: