交叉浏览器比较文件位置
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26-10-2019 - |
题
我想实现比较的题词。 RESIG做了一个 做到这一点的好开端. 。我已经拿了他的代码,使它整齐
function compareDocumentPosition(other) {
var ret = 0;
if (this.contains) {
if (this !== other && this.contains(other)) {
ret += 16;
}
if (this !== other && other.contains(this)) {
ret += 8;
}
if (this.sourceIndex >= 0 && other.sourceIndex >= 0) {
if (this.sourceIndex < other.sourceIndex) {
ret += 4;
}
if (this.sourceIndex > other.sourceIndex) {
ret += 2;
}
} else {
ret += 1;
}
}
return ret;
}
这适用于 Element
但不是 Text
或者 DocumentFragment
. 。这是因为IE8不给 .sourceIndex
在那些节点上。 (它不给 .contains
两者都已经解决了这个问题)
我如何有效地写 +=4
和 +=2
比对应的位 document_position_following 和 document_position_preceding.
对于额外的参考
如果a和b在同一树中,并且a以树顺序为b,则对象a在对象b之前。
如果a和b在同一树中,则一个对象A正在跟随对象B,并且A以树顺序为b。
树订单是预订,深度优先。
大多数现代浏览器实施此功能(包括IE9)。因此,您只需要在IE8中起作用的东西(我不在乎IE6/7,但是如果它起作用了!)
解决方案
function recursivelyWalk(nodes, cb) {
for (var i = 0, len = nodes.length; i < len; i++) {
var node = nodes[i];
var ret = cb(node);
if (ret) {
return ret;
}
if (node.childNodes && node.childNodes.length) {
var ret = recursivelyWalk(node.childNodes, cb);
if (ret) {
return ret;
}
}
}
}
function testNodeForComparePosition(node, other) {
if (node === other) {
return true;
}
}
function compareDocumentPosition(other) {
function identifyWhichIsFirst(node) {
if (node === other) {
return "other";
} else if (node === reference) {
return "reference";
}
}
var reference = this,
referenceTop = this,
otherTop = other;
if (this === other) {
return 0;
}
while (referenceTop.parentNode) {
referenceTop = referenceTop.parentNode;
}
while (otherTop.parentNode) {
otherTop = otherTop.parentNode;
}
if (referenceTop !== otherTop) {
return Node.DOCUMENT_POSITION_DISCONNECTED;
}
var children = reference.childNodes;
var ret = recursivelyWalk(
children,
testNodeForComparePosition.bind(null, other)
);
if (ret) {
return Node.DOCUMENT_POSITION_CONTAINED_BY +
Node.DOCUMENT_POSITION_FOLLOWING;
}
var children = other.childNodes;
var ret = recursivelyWalk(
children,
testNodeForComparePosition.bind(null, reference)
);
if (ret) {
return Node.DOCUMENT_POSITION_CONTAINS +
Node.DOCUMENT_POSITION_PRECEDING;
}
var ret = recursivelyWalk(
[referenceTop],
identifyWhichIsFirst
);
if (ret === "other") {
return Node.DOCUMENT_POSITION_PRECEDING;
} else {
return Node.DOCUMENT_POSITION_FOLLOWING;
}
}
我自己写了。我认为此实现是错误的,但这是我其他一些代码中的错误。似乎很扎实。
其他提示
Raynos的答案是最高的开始,但开箱即用。 Node.*
找不到 .bind
IE8中不可用。
这是准备在Internet Explorer 8中使用的代码:
function recursivelyWalk(nodes, cb) {
for (var i = 0, len = nodes.length; i < len; i++) {
var node = nodes[i];
var ret = cb(node);
if (ret) {
return ret;
}
if (node.childNodes && node.childNodes.length) {
var ret = recursivelyWalk(node.childNodes, cb);
if (ret) {
return ret;
}
}
}
}
function testNodeForComparePosition(node, other) {
if (node === other) {
return true;
}
}
var DOCUMENT_POSITION_DISCONNECTED = 1;
var DOCUMENT_POSITION_PRECEDING = 2;
var DOCUMENT_POSITION_FOLLOWING = 4;
var DOCUMENT_POSITION_CONTAINS = 8;
var DOCUMENT_POSITION_CONTAINED_BY = 16;
function compareDocumentPosition(thisNode, other) {
function identifyWhichIsFirst(node) {
if (node === other) {
return "other";
} else if (node === reference) {
return "reference";
}
}
var reference = thisNode,
referenceTop = thisNode,
otherTop = other;
if (this === other) {
return 0;
}
while (referenceTop.parentNode) {
referenceTop = referenceTop.parentNode;
}
while (otherTop.parentNode) {
otherTop = otherTop.parentNode;
}
if (referenceTop !== otherTop) {
return DOCUMENT_POSITION_DISCONNECTED;
}
var children = reference.childNodes;
var ret = recursivelyWalk(
children,
function(p) {
(function() {
var localOther = other;
return testNodeForComparePosition(localOther, p);
})();
}
);
if (ret) {
return DOCUMENT_POSITION_CONTAINED_BY +
DOCUMENT_POSITION_FOLLOWING;
}
var children = other.childNodes;
var ret = recursivelyWalk(
children,
function(p) {
(function() {
var localOther = reference;
return testNodeForComparePosition(localOther, p);
})();
}
);
if (ret) {
return DOCUMENT_POSITION_CONTAINS +
DOCUMENT_POSITION_PRECEDING;
}
var ret = recursivelyWalk(
[referenceTop],
identifyWhichIsFirst
);
if (ret === "other") {
return DOCUMENT_POSITION_PRECEDING;
} else {
return DOCUMENT_POSITION_FOLLOWING;
}
}
你这样称呼它:
compareDocumentPosition(sourceElement, elementToTest)
(就像打电话 sourceElement.compareDocumentPosition(elementToTest)
)
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