15

谁能告诉我 IE 7 和 IE 8 是否支持 JavaScript .indexOf() 方法，因为我收到错误：

SCRIPT438: Object doesn't support property or method 'indexOf'

从 IE9 调试控制台（在 IE7 和 IE8 浏览器模式下使用）。

对于下面的评论，使用 .indexOf() 的代码如下：

if(shirt_colour == 'black') {
    p_arr=['orange','red','green','yellow','bblue','rblue','pink','white','silver','gold'];
    if( p_arr.indexOf(print_colour) != -1 ) rtn = true;
}
4

3 回答 3

36

在 IE<9indexOf()上，它没有“很好”地实现。尝试在您的代码中添加此功能：

if (!Array.prototype.indexOf)
{
  Array.prototype.indexOf = function(elt /*, from*/)
  {
    var len = this.length;

    var from = Number(arguments[1]) || 0;
    from = (from < 0)
         ? Math.ceil(from)
         : Math.floor(from);
    if (from < 0)
      from += len;

    for (; from < len; from++)
    {
      if (from in this &&
          this[from] === elt)
        return from;
    }
    return -1;
  };
}

如果在 ECMA-262 标准中找不到，它将“替换”原始功能。

于 2012-07-18T15:34:32.633 回答
2

以下代码可能会有所帮助。

function findIndexOf(findfrom, findthis) {
    for (i = 0; i < findfrom.length; i++) {
        if (findfrom[i] == findthis) {
            return i;
        }
    }
    return -1;
}
于 2015-01-20T10:01:47.533 回答
0

如果你需要indexOf在 IE<=8 中，你应该考虑使用下面的polyfill，这是MDN 推荐的：

// Production steps of ECMA-262, Edition 5, 15.4.4.14
// Reference: http://es5.github.io/#x15.4.4.14
if (!Array.prototype.indexOf) {
  Array.prototype.indexOf = function(searchElement, fromIndex) {

    var k;

    // 1. Let o be the result of calling ToObject passing
    //    the this value as the argument.
    if (this == null) {
      throw new TypeError('"this" is null or not defined');
    }

    var o = Object(this);

    // 2. Let lenValue be the result of calling the Get
    //    internal method of o with the argument "length".
    // 3. Let len be ToUint32(lenValue).
    var len = o.length >>> 0;

    // 4. If len is 0, return -1.
    if (len === 0) {
      return -1;
    }

    // 5. If argument fromIndex was passed let n be
    //    ToInteger(fromIndex); else let n be 0.
    var n = +fromIndex || 0;

    if (Math.abs(n) === Infinity) {
      n = 0;
    }

    // 6. If n >= len, return -1.
    if (n >= len) {
      return -1;
    }

    // 7. If n >= 0, then Let k be n.
    // 8. Else, n<0, Let k be len - abs(n).
    //    If k is less than 0, then let k be 0.
    k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);

    // 9. Repeat, while k < len
    while (k < len) {
      // a. Let Pk be ToString(k).
      //   This is implicit for LHS operands of the in operator
      // b. Let kPresent be the result of calling the
      //    HasProperty internal method of o with argument Pk.
      //   This step can be combined with c
      // c. If kPresent is true, then
      //    i.  Let elementK be the result of calling the Get
      //        internal method of o with the argument ToString(k).
      //   ii.  Let same be the result of applying the
      //        Strict Equality Comparison Algorithm to
      //        searchElement and elementK.
      //  iii.  If same is true, return k.
      if (k in o && o[k] === searchElement) {
        return k;
      }
      k++;
    }
    return -1;
  };
}
于 2016-02-21T17:39:16.350 回答