JavaScript:将参数传递给回调函数
我试图将一些参数传递给用作回调的函数,我该怎么做?
function tryMe (param1, param2) {
alert (param1 + " and " + param2);
}
function callbackTester (callback, param1, param2) {
callback (param1, param2);
}
callbackTester (tryMe, "hello", "goodbye");
如果你想要更通用的东西,你可以像这样使用参数变量:
function tryMe (param1, param2) {
alert(param1 + " and " + param2);
}
function callbackTester (callback) {
callback (arguments[1], arguments[2]);
}
callbackTester (tryMe, "hello", "goodbye");
但除此之外,您的示例工作正常(参数[0]可用于代替测试仪中的回调)
这也将起作用:
// callback function
function tryMe (param1, param2) {
alert (param1 + " and " + param2);
}
// callback executer
function callbackTester (callback) {
callback();
}
// test function
callbackTester (function() {
tryMe("hello", "goodbye");
});
另一个场景:
// callback function
function tryMe (param1, param2, param3) {
alert (param1 + " and " + param2 + " " + param3);
}
// callback executer
function callbackTester (callback) {
//this is the more obivous scenario as we use callback function
//only when we have some missing value
//get this data from ajax or compute
var extraParam = "this data was missing" ;
//call the callback when we have the data
callback(extraParam);
}
// test function
callbackTester (function(k) {
tryMe("hello", "goodbye", k);
});
你的问题不清楚。 如果你问的是如何以更简单的方式做到这一点,你应该看看ECMAScript 5th edition方法.bind(),它是Function.prototype的成员。 使用它,你可以做这样的事情:
function tryMe (param1, param2) {
alert (param1 + " and " + param2);
}
function callbackTester (callback) {
callback();
}
callbackTester(tryMe.bind(null, "hello", "goodbye"));
您还可以使用下面的代码,如果它在当前浏览器中不可用,则添加该方法:
// From Prototype.js
if (!Function.prototype.bind) { // check if native implementation available
Function.prototype.bind = function(){
var fn = this, args = Array.prototype.slice.call(arguments),
object = args.shift();
return function(){
return fn.apply(object,
args.concat(Array.prototype.slice.call(arguments)));
};
};
}
例
bind() - PrototypeJS文档
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