How to simplify array onchange function
Question
I have 3 pulldown menus on the page. Upon user's selection, it will change the image and caption. The below is a part of an onLoad function that works. However, I am looking for a solution to combine these 3 essentially same functions.
I tried different ways to put variable as array index eg myChoice[x].onchange with for(x in array), etc., but can't make it work.
myChoice is a Select element array and necessary value is extracted for image and caption from it. myThumb is an Image element array. myDesc is a Span element array for caption.
I would really appreciate a good input. Thank you!
myChoice[0].onchange=function()
{
jpgfile=this.value;
filechar=jpgfile.length-3;
shortfile=jpgfile.substr(filechar,3);
myThumb[0].src=bp+'truffle'+shortfile+'.jpg';
captext=shortfile.substr(2,1);
myDesc[0].innerHTML=caption[captext];
}
myChoice[1].onchange=function()
{
jpgfile=this.value;
filechar=jpgfile.length-3;
shortfile=jpgfile.substr(filechar,3);
myThumb[1].src=bp+'truffle'+shortfile+'.jpg';
captext=shortfile.substr(2,1);
myDesc[1].innerHTML=caption[captext];
}
myChoice[2].onchange=function() {
jpgfile=this.value;
filechar=jpgfile.length-3;
shortfile=jpgfile.substr(filechar,3);
myThumb[2].src=bp+'truffle'+shortfile+'.jpg';
captext=shortfile.substr(2,1);
myDesc[2].innerHTML=caption[captext]; }
ENTIRE CODE WITH SUGGESTED FUNCTIONS
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css">
img.choicePic {
display:block;
}
h1 {
font-family:arial, Verdana, tahoma;
font-size:17pt;
text-align:center;
display:block;
}
#caption0, #caption1, #caption2 {
font-family:arial, Verdana, tahoma;
font-size:7pt;
text-align:left;
display:block;
}
</style>
<script type="text/javascript">
function setPicCap() {
var caption=['Select your chocolate',
'Flavors from India: nutmeg and subtle spices, in milk chocolate, dusted with cinnamon. ',
'Caribbean flavors of rum and butter mingle in a creamy center, dipped in dark chocolate. ',
'Dark chocolate truffle center, dipped in dark chocolate with white chocolate stripes. ',
]; // This will be your images description
var bp='images/store/', //base url of your images
imgnum=3; //Number of your images. This should match on your comboboxes options.
var myThumb=new Array(3), myDesc=new Array(3), myChoice=new Array(3);
for (i=0; i<imgnum; i++) {
numChoice=i.toString();
imgChoice="thumb"+numChoice;
capChoice="caption"+numChoice;
selectChoice="selection"+numChoice;
imgChoice=document.getElementById(imgChoice); //Image element. Use .src to view specific.
myThumb[i]=imgChoice;
capChoice=document.getElementById(capChoice); //Span element. Place holder. No value.
myDesc[i]=capChoice;
selectChoice=document.getElementById(selectChoice); //Select element. Use innerHTML to view specific.
myChoice[i]=selectChoice;
}
function updateThumb(index, jpgfile){
shortfile = jpgfile.substr(jpgfile.length - 3,3);
myThumb[index].src = bp + 'truffle' + shortfile + '.jpg';
captext = shortfile.substr(2,1);
myDesc[index].innerHTML = caption[captext];
}
for(var j = 0; j < myChoice.length; j++){
var idx = j;
myChoice.onchange = function(){
updateThumb(idx, this.value);
}
}
}
</script>
</head>
<body onLoad="setPicCap()">
<center>
<h1>Build Your Computer Test Script</h1>
</center>
<table width="800" align="center">
<tr>
<td><img src="images/store/select_a_chocolate.png" alt="Mukilteo Choclate Truffle" border="0" id="thumb0" class="choicePic"></td>
<td><select id="selection0" name="truffle">
<option value="0" selected >Select Your Chocolate</option>
<option value="Square0: BANGALORE SPICE Item 001|BANGALORE SPICE Item 001">BANGALORE SPICE Item 001</option>
<option value="Square0: BUTTERED RUM Item 002|BUTTERED RUM Item 002">BUTTERED RUM Item 002</option>
<option value="Square0: CLASSIC DARK CHOCOLATE Item 003|CLASSIC DARK CHOCOLATE Item 003">CLASSIC DARK CHOCOLATE Item 003</option>
</select>
<br></td>
</tr>
<tr>
<td colspan="2"><span id="caption0"></span></td>
</tr>
</table>
<br>
<br>
<br>
<table width="800" align="center">
<tr>
<td><img src="images/store/select_a_chocolate.gif" alt="Mukilteo Choclate Truffle" border="0" id="thumb1" class="choicePic"></td>
<td><select id="selection1" name="truffle">
<option value="0" selected >Select Your Chocolate</option>
<option value="Square1: BANGALORE SPICE Item 001|BANGALORE SPICE Item 001">BANGALORE SPICE Item 001</option>
<option value="Square1: BUTTERED RUM Item 002|BUTTERED RUM Item 002">BUTTERED RUM Item 002</option>
<option value="Square1: CLASSIC DARK CHOCOLATE Item 003|CLASSIC DARK CHOCOLATE Item 003">CLASSIC DARK CHOCOLATE Item 003</option>
</select>
<br></td>
</tr>
<tr>
<td colspan="2"><span id="caption1"></span></td>
</tr>
</table>
<br>
<br>
<br>
<table width="800" align="center">
<tr>
<td><img src="images/store/select_a_chocolate.jpg" alt="Mukilteo Choclate Truffle" border="0" id="thumb2" class="choicePic"></td>
<td><select id="selection2" name="truffle">
<option value="0" selected >Select Your Chocolate</option>
<option value="Square2: BANGALORE SPICE Item 001|BANGALORE SPICE Item 001">BANGALORE SPICE Item 001</option>
<option value="Square2: BUTTERED RUM Item 002|BUTTERED RUM Item 002">BUTTERED RUM Item 002</option>
<option value="Square2: CLASSIC DARK CHOCOLATE Item 003|CLASSIC DARK CHOCOLATE Item 003">CLASSIC DARK CHOCOLATE Item 003</option>
</select>
<br></td>
</tr>
<tr>
<td colspan="2"><span id="caption2"></span></td>
</tr>
</table>
</body>
</html>
2 answers
solution1
1 2011-01-15 08:16:22
function updateThumb(index, jpgfile){
shortfile = jpgfile.substr(jpgfile.length - 3,3);
myThumb[index].src = bp + 'truffle' + shortfile + '.jpg';
captext = shortfile.substr(2,1);
myDesc[index].innerHTML = caption[captext];
}
for(var i = 0; i < myChoice.length; i++){
var idx = i;
myChoice.onchange = function(){
updateThumb(idx, this.value);
}
}
solution2
0 2012-11-09 06:12:16
Here you go:
function setPicCap() {
function a(a, d) {
shortfile = d.substr(d.length - 3, 3), e[a].src = c + "truffle" + shortfile + ".jpg", captext = shortfile.substr(2, 1), f[a].innerHTML = b[captext]
}
var b = ["Select your chocolate", "Flavors from India: nutmeg and subtle spices, in milk chocolate, dusted with cinnamon. ", "Caribbean flavors of rum and butter mingle in a creamy center, dipped in dark chocolate. ", "Dark chocolate truffle center, dipped in dark chocolate with white chocolate stripes. "],
c = "images/store/",
d = 3,
e = Array(3),
f = Array(3),
g = Array(3);
for (i = 0; d > i; i++) numChoice = i + "", imgChoice = "thumb" + numChoice, capChoice = "caption" + numChoice, selectChoice = "selection" + numChoice, imgChoice = document.getElementById(imgChoice), e[i] = imgChoice, capChoice = document.getElementById(capChoice), f[i] = capChoice, selectChoice = document.getElementById(selectChoice), g[i] = selectChoice;
for (var h = 0; g.length > h; h++) {
var j = h;
g.onchange = function () {
a(j, this.value)
}
}
}
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