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/*
JavaScript Bible, Fourth Edition
by Danny Goodman
Publisher: John Wiley & Sons CopyRight 2001
ISBN: 0764533428
*/
<HTML>
<HEAD>
<TITLE>Changing Options On The Fly</TITLE>
<SCRIPT LANGUAGE="JavaScript">
// flag to reload page for older NNs
var isPreNN6 = (navigator.appName == "Netscape" && parseInt(navigator.appVersion) <= 4)
// initialize color list arrays
plainList = new Array(6)
hardList = new Array(6)
plainList[0] = "cyan"
hardList[0] = "#00FFFF"
plainList[1] = "magenta"
hardList[1] = "#FF00FF"
plainList[2] = "yellow"
hardList[2] = "#FFFF00"
plainList[3] = "lightgoldenrodyellow"
hardList[3] = "#FAFAD2"
plainList[4] = "salmon"
hardList[4] = "#FA8072"
plainList[5] = "dodgerblue"
hardList[5] = "#1E90FF"
// change color language set
function setLang(which) {
var listObj = document.forms[0].colors
var newOpt
// filter out old IE browsers
if (listObj.type) {
// find out if it's 3 or 6 entries
var listLength = listObj.length
// save selected index
var currSelected = listObj.selectedIndex
// replace individual existing entries
for (var i = 0; i < listLength; i++) {
newOpt = document.createElement("OPTION")
newOpt.text = (which == "plain") ? plainList[i] : hardList[i]
listObj.options.remove(i)
listObj.options.add(newOpt, i)
}
listObj.selectedIndex = currSelected
}
}
// create entirely new options list
function setCount(choice) {
var listObj = document.forms[0].colors
var newOpt
// filter out old browsers
if (listObj.type) {
// get language setting
var lang = (document.forms[0].geekLevel[0].checked) ? "plain" : "hard"
// empty options from list
while (listObj.options.length) {
listObj.options.remove(0)
}
// create new option object for each entry
for (var i = 0; i < choice.value; i++) {
newOpt = document.createElement("OPTION")
newOpt.text = (lang == "plain") ? plainList[i] : hardList[i]
listObj.options.add(newOpt)
}
listObj.options[0].selected = true
}
}
</SCRIPT>
</HEAD>
<BODY>
<H1>Flying Select Options</H1>
<FORM>
Choose a palette size:
<INPUT TYPE="radio" NAME="paletteSize" VALUE=3
onClick="setCount(this)" CHECKED>Three
<INPUT TYPE="radio" NAME="paletteSize" VALUE=6
onClick="setCount(this)">Six
<P>
Choose geek level:
<INPUT TYPE="radio" NAME="geekLevel" VALUE=""
onClick="setLang('plain')" CHECKED>Plain-language
<INPUT TYPE="radio" NAME="geekLevel" VALUE=""
onClick="setLang('hard')">Gimme hex-triplets!
<P>
Select a color:
<SELECT NAME="colors">
<OPTION SELECTED>cyan
<OPTION>magenta
<OPTION>yellow
</SELECT>
</FORM>
</BODY>
</HTML>
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