在表单加载时显示Ajax样本结果

Question

I've set up a box to display results from an Ajax form, showing water data from US Geological Survey and using a Google chart. Works great, but I want users to see some sample results when they first load the form instead of an empty box. Not sure how to do it. Here's the code for the form:

<table bgcolor="tan" width="480px" height="450px"><tr><td>
<h2>Current River Levels</h2></td><td>
<form>
<select name="users"; onchange="showUser(this.value); drawChart(this.value)";>
<option value="01598500">North Branch at Luke, MD</option>
<option value="01603000">North Branch at Cumberland, MD</option>
<option value="01610000">Potomac River at Paw Paw, WV</option>
<option value="01613000">Potomac River at Hancock, MD</option>
<option value="01619500">Antietam Creek at Sharpsburg, MD</option>
<option value="01638500">Potomac River at Point of Rocks, MD</option>
<option value="01648000">Rock Creek at Sherrill Drive, DC</option>
<option value="01646500">Little Falls, DC</option>
</select>
</form></td></tr><td colspan="2">
<div id="placeholder"></div>
<div id="placeholder2"></div>## 
<div id="chart" style="width:100%"></div>
<div id="txtHint"><b>Select a site or visit our <a href="../monitoring_map.php4" target="_blank">interactive map.</a></b></div>

The entire project is located here: http://www.riverexplorer.com/potomax/json_test_20.php

Answer 1

Trigger the onchange event when the document is ready.

$(function(){
    $('select[name="users"]').trigger('change');
 });