JavaScriptAjaxJson achieves linkage between upper and lower-level drop-down boxes

Recently, I tried to create a drop-down box linkage function for departments and personnel. The relationship between departments and personnel is 1: N [html] & lt; divclass & quot; forntName & quot; & gt; department & lt;/div & gt; & lt; divclass & quot; inpBox & quot; & gt; & lt; selectname & quot; department & qu recently tried to create a drop-down box linkage function for departments and personnel. The relationship between departments and personnel is 1: N [html] department. Select'>Personnel '>The onchange () event in the department drop-down box uses an AJAX method to return a JSON object (a list is put in JSON ). Js Method on this page: [javascript]