Practice Set, Week 8, DOM Traversal

by Keeley Peck

HTML

<h3>Practice Set, Week 8, DOM Traversal</h3>

<p>Code is provided here that will traverse the DOM. Your job is to add some code that will take some action at each node.</p>
<p>Your task is to find every element that has the word "text" in it, and add the className "searchHit" to their parent elements.</p>
<p>The steps to do this will look something like this:</p>
<ol>
    <li>At each node, determine if it's a text node</li>
    <li>If so, find out if the target string is within the text content of the node.</li>
    <li>If so, get the parent node and set its class attribute to "searchHit"</li>
</ol>
<p>If you've got it, each element containing the word 'text' will be highlighted in yellow. </p>

CSS

.searchHit {
    background-color:yellow;
}

JavaScript

function traverse(el, str) {
    
    for (var i = 0; i < el.childNodes.length; i++) {
        traverse(el.childNodes[i], str);
    }
    
    // Find each text node
    if (el.nodeType == 3) {
    	// check text nodes for data type of string containing the str parameter
      // (which we designate as 'text' when we call the function at the bottom)
      if ((typeof el.nodeValue == "string") && (el.nodeValue.indexOf(str) != -1)) {
      	// set the parent node class to "searchHit" 
      	el.parentNode.setAttribute("class", "searchHit");
      }    	
    }   
}
// call the function to traverse, looking for the word 'text'
traverse(document.documentElement, 'text');