试图更改onchange中的所有数字 - onchange.replace不起作用？

Question

I have an xsl page which uses

 <xsl:variable name="pos" select="Position()"/> 

in the onchange events

onchange="updateDropdown({$pos});someElement_{$pos}.value = {$pos}";

When evaluated on page p=load this will be read as

onchange="updateDropdown(1);someElement_1.value = 1";
onchange="updateDropdown(2);someElement_2.value = 2";
onchange="updateDropdown(3);someElement_3.value = 3";

When I add a row to the bottom of this using a button which copies the entire first row to the bottom it had to go through and update these numbers because it is not handled

I do

lastRowEl = rowEls[rowEls.length-1];

then

lastRowEl.id = "element_" + rowEls.length
lastRowEl.value = "";

finally,

lastRowEl.onchange = lastRowEl.onchange.replace(/\d/g, rowEls.length)

id gets changed to element_4 value gets modified to blank

but onchange.replace does not work and so onchange remains as

onchange="updateDropdown(1);someElement_1.value = 1";

instaead of

onchange="updateDropdown(4);someElement_4.value = 4";

How can I replace all numbers in an onchange function and reset the onchange function with the numbers modified for the element in the last row?

Thanks

Answer 1

This seems a bit weird and I wonder why it works at all, since the value returned by your lastRowEl.onchange is most likely a Function and not a String. Some automatic toString() call seems to happen on your platform (doesn't work when I test this in Safari). However, the result will most likely be a multiline string and you will probably need to use multiline RegExps, eg /\\d/mg .

Even if this works it is pretty ugly. What about defining a function which does all the calls you put into your handler?

function onchangeHandler(index) {
    updateDropdown(index);
    window["someElement_" + index].value = index;
}

You would then assign these handler functions in HTML

< ... onchange="onchangeHandler(1);" .... />

and update them in Javascript

(function() {
    var index = rowEls.length;
    lastRowEl.onchange = function() {onchangeHandler(index);};
})();

Note that the closure around the assignment is may not be necessary depending on your surrounding code. You will most likely need the explicit index variable definition, though.

Answer 2

Try the following solution

var onch = new String(lastRowEl.onchange); 
onch = onch.replace(/\d/g, rowEls.length);

lastRowEl.onchange = new Function(onch);

This will work as you expect.

Hope this solves your problem.