html code :
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script type="text/javascript" src="script.js">
</script>
</head>
<body bgcolor="#FFFFCC">
<center>
<form>
<select id="newLocation">
<option value="1.jpg">index</option>
<option value="script.js">posts</option>
<option value="2.jpg" selected="selected">blog</option>
</select>
</form>
javascript :
window.onload = startInit;
function startInit() {
document.getElementById("newLocation").selectedIndex = 0;
document.getElementById("newLocation").onchange = jumpPage;
}
function jumpPage() {
var newLoc = document.getElementById("newLocation");// what does this statement return ?
var newPage = newLoc.options[newLoc.getSelectedIndex].value;
if(newPage != "")
window.location = newPage;
}
Why don't get to to new page i.e the value when i select an option from the com开发者_JAVA百科bo box ?
Also what does document.getElementById("newLocation"); this statement (the first statement of the function jumpPage) return ?
You can try
var newPage = newLoc.options[newLoc.selectedIndex].value;
The statement
var newLoc = document.getElementById("newLocation");
just finds the DOM (HTML) element <... id="newLocation" ...>, i.e. your <select id="newLocation"> .
document.getElementById("newLocation") will return you the SELECT object (i.e., the reference to your drop-down).
Regarding the JS, it has an error. You should change newLoc.getSelectedIndex to newLoc.selectedIndex.
![Interactive visualization of a graph in python [closed]](https://www.devze.com/res/2023/04-10/09/92d32fe8c0d22fb96bd6f6e8b7d1f457.gif)
加载中,请稍侯......
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