For loop in Javascript runs only once

Question

Here is my code. I do not quite understand why the for loop runs only once, both inner and outer. nodeList.length and innerNodeList.length show appropriate values when I generate alert messages. I see that both i and j do not increment beyond 0. Kindly point out anything wrong with the code.

function getCategoryElements() {
var newCategoryDiv = document.getElementById("category");
var nodeList = newCategoryDiv.childNodes;

for (var i = 0; i < nodeList.length; ++i) {
    var innerNodeList = nodeList[i].childNodes;
    alert("innerNodeList Length" + innerNodeList.length.toString());

    for (var j = 0; j < innerNodeList.length; ++j) {
        if (innerNodeList[j].nodeName == "SELECT") {
            alert("inside select Node value " + innerNodeList[j].nodeValue.toString());
            document.getElementById("newCategories").value = 
                document.getElementById("newCategories").value + '<%=delimiter%>' + innerNodeList[j].nodeValue;
        } else if (innerNodeList[j].nodeName == "TEXTAREA") {
            document.getElementById("newCategoriesData").value =
                document.getElementById("newCategoriesData").value + '<%=delimiter%>' + innerNodeList[j].nodeValue;
        }
    }
  }
}

console.log the nodeList.length and innerNodeList.length. Im sure youll find that they are both equal to 1. Make a fiddle or post your HTML so we can see how the category div is set up. — Kierchon
– Kierchon, Commented Oct 18, 2013 at 16:02
Why are you putting var i outside loop statement? You can do: for (var i = 0; i < nodeList.length; ++i) {....} — Nick Louloudakis
– Nick Louloudakis, Commented Oct 18, 2013 at 16:04
we'll also need more context - the error could be something as basic as the fact that your array only has 1 element. — Overcode
– Overcode, Commented Oct 18, 2013 at 16:04

Vivian River · Accepted Answer · 2013-10-18 19:33:55Z

1

var newCategoryDiv, nodeList, innerNodeList, innerNode, i, j;

newCategoryDiv = document.getElementById("category");
nodeList = newCategoryDiv.childNodes;

for (i = 0; i < nodeList.length; ++i) {
    innerNodeList = nodeList[i].childNodes;
    alert("innerNodeList Length" + innerNodeList.length.toString());

    for (j = 0; j < innerNodeList.length; ++j) {
        innerNode = innerNodeList[j];
        if (innerNode.nodeName === "SELECT") {
            alert("inside select Node value " + innerNode.nodeValue.toString());
            document.getElementById("newCategories").value += '<%=delimiter%>' + innerNode.nodeValue;
        } else if (innerNode.nodeName === "TEXTAREA") {
            document.getElementById("newCategoriesData").value += '<%=delimiter%>' + innerNode.nodeValue;
        }
        // Will this work?
        alert('Does this alert appear'); 
    }
}

I took the liberty to refactor your code and clean it up a little bit. In case you're not aware, all variables have function scope in Javascript, so no matter where you declare them within a single function, Javascript treats them as if the variable declaration is the first statement.

It appears that your code is syntactically correct, and so I think that the most logical place to look for a problem is that there could be an error occurring after the last alert function call.

In order to check this, try adding another alert function call to the end of the inner loop. If it doesn't run, you'll know this is the case.

edited Oct 18, 2013 at 19:33

answered Oct 18, 2013 at 19:25

Vivian River

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1 Comment

user592748 Over a year ago

Thanks. This helps. The last alert was not appearing. I looked at console under developer tools, there were perhaps 2 errors. toString was throwing up error as @epascarello pointed out. Also, '<%=delimiter%>' was throwing an error. When both corrected, the error was that node.value was null. Hence, I used <portlet:namespace /> to retrieve both elements.

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