javascript选择输入事件

Question

我正在尝试从javascript创建一个选择输入并将函数绑定到用户更改选项时.到目前为止,我有:

filter.change = function() {
    console.log("CHANGED");
}

但在选择别的东西时没有任何反应.这段代码有什么问题.另外,如何在函数中获取新选择的值？就像是:

console.log(this.value + "has been selected")

Answer 1

你很亲密,你需要使用onchange:

filter.onchange = function() {
    alert("CHANGED");
    //You can alert the value of the selected option, using this:
    alert(this.value + " was selected");
}

当然,正如德兰所说,你应该尽可能addEventListener(和attachEvent).例:

//Define a onchange handler:
var changeHandler = function() {
    alert("CHANGED");
    //You can alert the value of the selected option, using this:
    alert(this.value + " was selected");
}
//First try using addEventListener, the standard method to add a event listener:
if(filter.addEventListener)
  filter.addEventListener("change", changeHandler, false);
//If it doesn't exist, try attachEvent, the IE way:
else if(filter.attachEvent)
  filter.attachEvent("onchange", changeHandler);
//Just use onchange if neither exist
else
  filter.onchange = changeHandler;

Answer 2

如果使用这种方式,属性名称为onchange:

filter.onchange = function() {
     alert(this.value + "has been selected");
};

更多的信息:

• MDN - HTMLSelectElement
• quirksmode.org - 传统的事件注册模型

注意:还有另一种注册事件处理程序的方法,它允许为同一事件分配多个事件处理程序.有关更多信息,请查看quirksmode.org - 高级事件注册模型.