How to load second DropDown list from Database after first DropDownList is changed

Question

I am building a Web App. At some point a user needs to input data to a form. This form has several text fields and DropDownLists.

One of the DDLs is dep

Answer 1

If the data in the second drop-down is dependent on the data in the first, then you will have to load the values of the second dropdown into a javascript object, like so:

// Given the options in the first dropdown are: "foo", "bar", and "baz"
var secondData = {
    foo: ['lorem', 'ipsum'],
    bar: [1,2,3],
    baz: []
}

Add a 'change' event to the first dropdown, and given the value of that dropdown, load the contents of the second dropdown with the values contained in the secondData object.