我有一个带参数的callback,如何把参数传递给callback呢?
// callback function
function tryMe (param1, param2) {
alert (param1 + " and " + param2);
}
我从stackoverflow中看到几个非常漂亮的答案:https://stackoverflow.com/questions/3458553/javascript-passing-parameters-to-a-callback-function
法一:在callback函数tryMe
外面封装一个无参的匿名函数,在匿名函数内部显示调用参数:
// callback function
function tryMe (param1, param2) {
alert (param1 + " and " + param2);
}
// callback executer
function callbackTester (callback) {
callback();
}
// test function
callbackTester (function() {
tryMe("hello", "goodbye");
});
法二:类似法一,不过匿名函数保留一个参数,供调用函数callbackTester
在调用匿名函数时,由callbackTester
决定传什么参数进去。
// 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);
});
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