创建范围

HTML

<section id="wrap">
    <article id="main">
        <h1>游子吟</h1>
        <h2>孟郊</h2>
        <p>慈母手中线，游子身上衣。临行密密缝，意恐迟迟归。谁言寸草心，报得三春晖。</p>
    </article>
    <header>
        <input type="button" value="创建范围" onclick="createrange()" />
    </header>
    <footer>
        <dl>
            <dt>范围1</dt>
            <dd>Start Container(开始点的父节点）:<span id="txtStartContainer1"></span></dd>
            <dd>Start Offset(开始点的偏移值）:<span id="txtStartOffset1"></span></dd>
            <dd>End Container(结束点的父节点）:<span id="txtEndContainer1"></span></dd>
            <dd>End Offset(结束点的偏移值）:<span id="txtEndOffset1"></span></dd>
            <dd>Common Ancestor（共同祖先节点）:<span id="txtCommonAncestor1"></span></dd>
        </dl>
        <dl>
            <dt>范围2</dt>
            <dd>Start Container(开始点的父节点）:<span id="txtStartContainer2"></span></dd>
            <dd>Start Offset(开始点的偏移值）:<span id="txtStartOffset2"></span></dd>
            <dd>End Container(结束点的父节点）:<span id="txtEndContainer2"></span></dd>
            <dd>End Offset(结束点的偏移值）:<span id="txtEndOffset2"></span></dd>
            <dd>Common Ancestor（共同祖先节点）:<span id="txtCommonAncestor2"></span></dd>
        </dl>
    </footer>
</section>
    					    

JS

function createrange() {
    var range1 = document.createRange();
    var range2 = document.createRange();
    var main= document.getElementById("main");
    range1.selectNode(main);
    range2.selectNodeContents(main);
    var footer = document.getElementsByTagName("footer")[0];
	footer.style.display = "block";
    document.getElementById("txtStartContainer1").textContent = range1.startContainer.tagName;
    document.getElementById("txtStartOffset1").textContent = range1.startOffset;
    document.getElementById("txtEndContainer1").textContent = range1.endContainer.tagName;
    document.getElementById("txtEndOffset1").textContent = range1.endOffset;
    document.getElementById("txtCommonAncestor1").textContent = range1.commonAncestorContainer.tagName;

    document.getElementById("txtStartContainer2").textContent = range2.startContainer.tagName;
    document.getElementById("txtStartOffset2").textContent = range2.startOffset;
    document.getElementById("txtEndContainer2").textContent = range2.endContainer.tagName;
    document.getElementById("txtEndOffset2").textContent = range2.endOffset;
    document.getElementById("txtCommonAncestor2").textContent = range2.commonAncestorContainer.tagName;
}