根据可见性启动和停止 AJAX 更新。您可以使用.is()返回 TRUE 或 FALSE:visible:
var timer; // Variable to start and top updating timer
// This if statement has to be part of the event handler for the visibility
// change of selector..... so there might be more straight forward solution
// see the last example in this answer.
if ($(selector).is(":visible"))
{
// Start / continue AJAX updating
timer = setInterval(AJAXupdate, 1000);
} else
{
// Stop AJAX updating
clearInterval(timer);
}
这是一个定时器的简单示例,当它不可见时就会停止。请注意,当数字不可见时,它们不会继续增加:
(function() {
var switcher; // variable to start and stop timer
// Function / event that will be started and stopped
function count() {
$("div").html(1 + parseInt($("div").html(), 10));
}
$(function() { // <== doc ready
// Start timer - it is visible by default
switcher = setInterval(count, 1000);
$("input").click(function() {
$("div").toggle(); // Toggle timer visibility
// Start and stop timer based on visibility
if ($("div").is(":visible"))
{
switcher = setInterval(count, 1000);
} else
{
clearInterval(switcher);
}
});
});
}());
jsFiddle 示例
当然,在上述情况下,也许您的情况下,简单地交替打开和关闭更新会更直接:
(function() {
var switcher;
function count() {
$("div").html(1 + parseInt($("div").html(), 10));
}
$(function() {
switcher = setInterval(count, 1000);
$("input").toggle(function() {
clearInterval(switcher);
$("div").toggle(); },
function() {
switcher = setInterval(count, 1000);
$("div").toggle();
});
});
}());
jsFiddle 示例