如何使用AJAX解析XML文档以查看元素是否存在以及是否存在，将其传递给PHP文件

I have been stuck on this for the past couple days. The exact question is :

"Using Ajax write an application that allows the user to enter an item name (from above XML and display a relevant message if found in the document and the information about the item quantity"

XML File :

<?xml version="1.0" encoding="UTF-8"?>
<Recipe>
    <Name>Lime Jello Marshmellow Cottage Cheese Suprise</Name>
    <Description>My grandma's favourite (may she rest in peace).</Description>
    <Ingredients>
        <Ingredient>
            <Qty unit="box">1</Qty>
            <Item>Lime Gelatin</Item>
        </Ingredient>
        <Ingredient>
            <Qty unit="g">500</Qty>
            <Item>Multi Coloured tiny marshmallows</Item>
        </Ingredient>
        <Ingredient>
            <Qty unit="ml">500</Qty>
            <Item>Cottage Cheese</Item>
        </Ingredient>
        <Ingredient>
            <Qty unit="dash"/>
            <Item optional="1">Tabasco sauce</Item>
        </Ingredient>
    </Ingredients>
    <Instruction>
        <step>Prepare line gelatin according to package instructions</step>
    </Instruction>
</Recipe>