问题
I have several dropdown select menus where a selection of the first changes the options of the second and a selection on the second changes the options of the third, and so on.
I would like to remotely simulate a change (i.e. without the user clicking in the select menu) in the dropdown menu which will activate the Javascript to set the next dropdown's options.
Just setting the value of the select menu - document.getElementById('...').value='....' - does not stimulate the Javascript events on the dropdowns.
Note: I do not have access to the Javascript controlling the select menus nor do I know which trigger it looks for on the select menus (I am assuming "onselect").
I am using Javascript and the jQuery library. I need the solution to, of course, work cross browser.
Here is the whole js code (seems to be in prototype) that sets the listeners for the dropdowns:
/**************************** CONFIGURABLE PRODUCT **************************/
Product.Config = Class.create();
Product.Config.prototype = {
initialize: function(config){
this.config = config;
this.taxConfig = this.config.taxConfig;
this.settings = $$('.super-attribute-select');
this.state = new Hash();
this.priceTemplate = new Template(this.config.template);
this.prices = config.prices;
this.settings.each(function(element){
Event.observe(element, 'change', this.configure.bind(this))
}.bind(this));
// fill state
this.settings.each(function(element){
var attributeId = element.id.replace(/[a-z]*/, '');
if(attributeId && this.config.attributes[attributeId]) {
element.config = this.config.attributes[attributeId];
element.attributeId = attributeId;
this.state[attributeId] = false;
}
}.bind(this))
// Init settings dropdown
var childSettings = [];
for(var i=this.settings.length-1;i>=0;i--){
var prevSetting = this.settings[i-1] ? this.settings[i-1] : false;
var nextSetting = this.settings[i+1] ? this.settings[i+1] : false;
if(i==0){
this.fillSelect(this.settings[i])
}
else {
this.settings[i].disabled=true;
}
$(this.settings[i]).childSettings = childSettings.clone();
$(this.settings[i]).prevSetting = prevSetting;
$(this.settings[i]).nextSetting = nextSetting;
childSettings.push(this.settings[i]);
}
// Set default values - from config and overwrite them by url values
if (config.defaultValues) {
this.values = config.defaultValues;
}
var separatorIndex = window.location.href.indexOf('#');
if (separatorIndex != -1) {
var paramsStr = window.location.href.substr(separatorIndex+1);
var urlValues = paramsStr.toQueryParams();
if (!this.values) {
this.values = {};
}
for (var i in urlValues) {
this.values[i] = urlValues[i];
}
}
this.configureForValues();
document.observe("dom:loaded", this.configureForValues.bind(this));
},
configureForValues: function () {
if (this.values) {
this.settings.each(function(element){
var attributeId = element.attributeId;
element.value = (typeof(this.values[attributeId]) == 'undefined')? '' : this.values[attributeId];
this.configureElement(element);
}.bind(this));
}
},
configure: function(event){
var element = Event.element(event);
this.configureElement(element);
},
configureElement : function(element) {
this.reloadOptionLabels(element);
if(element.value){
this.state[element.config.id] = element.value;
if(element.nextSetting){
element.nextSetting.disabled = false;
this.fillSelect(element.nextSetting);
this.resetChildren(element.nextSetting);
}
}
else {
this.resetChildren(element);
}
this.reloadPrice();
// Calculator.updatePrice();
},
reloadOptionLabels: function(element){
var selectedPrice;
if(element.options[element.selectedIndex].config){
selectedPrice = parseFloat(element.options[element.selectedIndex].config.price)
}
else{
selectedPrice = 0;
}
for(var i=0;i<element.options.length;i++){
if(element.options[i].config){
element.options[i].text = this.getOptionLabel(element.options[i].config, element.options[i].config.price-selectedPrice);
}
}
},
resetChildren : function(element){
if(element.childSettings) {
for(var i=0;i<element.childSettings.length;i++){
element.childSettings[i].selectedIndex = 0;
element.childSettings[i].disabled = true;
if(element.config){
this.state[element.config.id] = false;
}
}
}
},
fillSelect: function(element){
var attributeId = element.id.replace(/[a-z]*/, '');
var options = this.getAttributeOptions(attributeId);
this.clearSelect(element);
element.options[0] = new Option(this.config.chooseText, '');
var prevConfig = false;
if(element.prevSetting){
prevConfig = element.prevSetting.options[element.prevSetting.selectedIndex];
}
if(options) {
var index = 1;
for(var i=0;i<options.length;i++){
var allowedProducts = [];
if(prevConfig) {
for(var j=0;j<options[i].products.length;j++){
if(prevConfig.config.allowedProducts
&& prevConfig.config.allowedProducts.indexOf(options[i].products[j])>-1){
allowedProducts.push(options[i].products[j]);
}
}
} else {
allowedProducts = options[i].products.clone();
}
if(allowedProducts.size()>0){
options[i].allowedProducts = allowedProducts;
element.options[index] = new Option(this.getOptionLabel(options[i], options[i].price), options[i].id);
element.options[index].config = options[i];
index++;
}
}
}
},
getOptionLabel: function(option, price){
var price = parseFloat(price);
if (this.taxConfig.includeTax) {
var tax = price / (100 + this.taxConfig.defaultTax) * this.taxConfig.defaultTax;
var excl = price - tax;
var incl = excl*(1+(this.taxConfig.currentTax/100));
} else {
var tax = price * (this.taxConfig.currentTax / 100);
var excl = price;
var incl = excl + tax;
}
if (this.taxConfig.showIncludeTax || this.taxConfig.showBothPrices) {
price = incl;
} else {
price = excl;
}
var str = option.label;
if(price){
if (this.taxConfig.showBothPrices) {
str+= ' ' + this.formatPrice(excl, true) + ' (' + this.formatPrice(price, true) + ' ' + this.taxConfig.inclTaxTitle + ')';
} else {
str+= ' ' + this.formatPrice(price, true);
}
}
return str;
},
formatPrice: function(price, showSign){
var str = '';
price = parseFloat(price);
if(showSign){
if(price<0){
str+= '-';
price = -price;
}
else{
str+= '+';
}
}
var roundedPrice = (Math.round(price*100)/100).toString();
if (this.prices && this.prices[roundedPrice]) {
str+= this.prices[roundedPrice];
}
else {
str+= this.priceTemplate.evaluate({price:price.toFixed(2)});
}
return str;
},
clearSelect: function(element){
for(var i=element.options.length-1;i>=0;i--){
element.remove(i);
}
},
getAttributeOptions: function(attributeId){
if(this.config.attributes[attributeId]){
return this.config.attributes[attributeId].options;
}
},
reloadPrice: function(){
var price = 0;
var oldPrice = 0;
for(var i=this.settings.length-1;i>=0;i--){
var selected = this.settings[i].options[this.settings[i].selectedIndex];
if(selected.config){
price += parseFloat(selected.config.price);
oldPrice += parseFloat(selected.config.oldPrice);
}
}
optionsPrice.changePrice('config', {'price': price, 'oldPrice': oldPrice});
optionsPrice.reload();
return price;
if($('product-price-'+this.config.productId)){
$('product-price-'+this.config.productId).innerHTML = price;
}
this.reloadOldPrice();
},
reloadOldPrice: function(){
if ($('old-price-'+this.config.productId)) {
var price = parseFloat(this.config.oldPrice);
for(var i=this.settings.length-1;i>=0;i--){
var selected = this.settings[i].options[this.settings[i].selectedIndex];
if(selected.config){
var parsedOldPrice = parseFloat(selected.config.oldPrice);
price += isNaN(parsedOldPrice) ? 0 : parsedOldPrice;
}
}
if (price < 0)
price = 0;
price = this.formatPrice(price);
if($('old-price-'+this.config.productId)){
$('old-price-'+this.config.productId).innerHTML = price;
}
}
}
}
all the select menus have the class "super-attribute-select"
回答1:
For this
<select name="blah">
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
You would
$('select[name="blah"]').val(3).trigger('change');
Don't know if you're looking for .trigger('select'); or trigger('onselect'); but I've never used those.
Demo
回答2:
Somethinkg like this may work:
$('select option[value=yourValue]').click();
Or:
$('select').find('option[value=yourValue]').attr('selected', 'selected').end().trigger('onselect');
来源：https://stackoverflow.com/questions/14305766/how-to-remotely-simulate-a-dropdown-selection