How to click a "select option" and then evaluate loaded content with casperjs

Question

I'm trying to crawl the sizes for this product:

Link to product

The problem: The sizes are loaded after the color of the product is selected.

In the product page's source code, I can see that the dropdown has a onchange-method: It clicks the form #postColor onchange.

The select dropdown:

<select name="color" id="color" class="cposelect" onchange="document.getElementById('postColor').click();" style="width:150px;margin-right: 20px; float: left;">
    <option selected="selected" onfocus="if (this.storeCurrentControl != null) storeCurrentControl(event, this);" value="0">Select colour</option>
    <option onfocus="if (this.storeCurrentControl != null) storeCurrentControl(event, this);" value="-8027">Light Camel</option>
    <option onfocus="if (this.storeCurrentControl != null) storeCurrentControl(event, this);" value="-9999">black</option>
</select>

The #postColor form, which is clicked onchange:

<input type="submit" name="postColor" value="" onclick="location.href=('./?model=10344-4180&amp;color='+document.forms[0].color.value+'&amp;size='+document.forms[0].size.value+'&amp;addbread=OUTLET&amp;addbread2=DRIZIA&amp;currentimage='+document.getElementById('currentimage').value+'&amp;selectedmi=a1_INDEX_14&amp;prev=10850-4314&amp;next=10413-4183'); return false;" id="postColor" class="cpobutton " style="display: none;">

This is my code so far and it's not working:

casper.start('http://shop.baumundpferdgarten.com/showmodel/?model=10344-4180&addbread=OUTLET&addbread2=DRIZIA&color=0&currentimage=1&selectedmi=a1_INDEX_14', function() {
    this.test.assertExists('select[name="color"] option:nth-child(2)');
    this.click('select[name="color"] option:nth-child(2)');
    this.waitForSelector('select[name="size"] option:nth-child(2)', function() {
        this.test.pass('selector is !');
        var sizes = this.evaluate(function() {
            console.log("======== evaluating ========");
            // var sizes = document.querySelectorAll('#size option');
            return document.querySelectorAll('#size option');
        });
        for (var i = sizes.length - 1; i >= 0; i--) {
            console.log(sizes[i].innerText);
        }
    });
});

I suspect that problem is that a totally new page is loaded when a color is clicked (the sizes are not dynamically appended).

How would you solve this problem?

Answer 1

This is how I do it

this.evaluate(function() {
    $('#select_element_selector').val('value').change();
});

The change() is very important

I'm assuming that you have jQuery on the page