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XML DOM replaceData() Method

❮ Comment Object


The following code fragment loads "books_comment.xml" into xmlDoc and replace "Simple" with "Easy" in the comment node of the first <book> element:

var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
   if (this.readyState == 4 && this.status == 200) {
xhttp.open("GET", "books_comment.xml", true);

function myFunction(xml) {
    var x, i, txt, xmlDoc;
    xmlDoc = xml.responseXML;
   txt = "";
    x = xmlDoc.getElementsByTagName("book")[0].childNodes;
    for (i = 0; i < x.length; i++) {
    // Process only comment nodes
        if (x[i].nodeType == 8) {
            x[i].replaceData(4, 6, "Easy");
            txt += x[i].data + "<br>";
    document.getElementById("demo").innerHTML = txt;


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In the example above we use a loop and an if-test to make sure we only process comment nodes. A comment node has a node type of 8.

Definition and Usage

The replaceData() method replaces data in a comment node.



Parameter Description
start Required. Specifies where to begin replacing characters. Start value starts at zero
length Required. Specifies how many characters to replace
string Required. Specifies the string to insert

❮ Comment Object