Executing a javascript function when the page loads

Within my asp.net website, in the .aspx file, the following code is present:

<script type="text/javascript">
    function callme(option) {
        document.getElementById("t1").value = option;
    }
</script>
<div id="content" runat="server"></div>

<input type="text" id="t1" />

In the code behind file within the Page_Load method:

content.InnerHtml = MyClassObject.MyMethod(...);

Inside MyClass:

public String MyMethod(...)
{
   ... //some code
   String str1 ="<select id=\"s1\" onchange=\"callme(this.value)\">" +
                    "  <option value=\"1\">One</option>"+
                    "  <option value=\"2\">Two</option>" +
                    "  <option value=\"3\">Three</option>" +                          
                    "</select>";
   ... // some code
   return str1;

Even though selecting an option from the dropdownlist updates the textbox t1 with its value, the textbox remains empty on page load. Since the dropdownlist values are dynamic, how can I automatically set the value of the first option in the dropdownlist to be displayed in the textbox t1 upon page load?

Answer №1

To retrieve the currently selected value from a dropdown list within your onload function in JavaScript, you can use the following code:

var dropdown = document.getElementById("dropdown");
var selectedValue = dropdown.options[dropdown.selectedIndex].value;

Answer №2

<script type="text/javascript">
function PurchaseG2() {
    alert('Hello jQuery!');
}
</script> //jQuery script block
protected void Page_Load(object sender, EventArgs e)
{
    ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "temp",
        "<script type='text/javascript'>PurchaseG2();</script>", false);
} //Handling ASP Button Click Events

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