Question

启动此功能时遇到一些问题我做错了什么？

我想在菜单到达“topb”部分时开始写作。

这是我的尝试：

var $el = $('.writer'),
    txt = $el.text(),
    txtLen = txt.length,
    timeOut,
    $topb = $('#topb'),
    char = 0;

$el.text('|');

if (topb.hasClass('active')) {
    (function typeIt() {
        var humanize = Math.round(Math.random() * (200 - 30)) + 30;
        timeOut = setTimeout(function () {
            char++;
            var type = txt.substring(0, char);
            $el.text(type + '|');
            typeIt();

            if (char == txtLen) {
                $el.text($el.text().slice(0, -1)); // remove the '|'
                clearTimeout(timeOut);
            }
        }, humanize);
    }())
};

这是原始功能

var $el = $('.writer'),
    txt = $el.text(),
    txtLen = txt.length,
    timeOut,
    char = 0;

$el.text('|');

(function typeIt() {
    var humanize = Math.round(Math.random() * (200 - 30)) + 30;
    timeOut = setTimeout(function () {
        char++;
        var type = txt.substring(0, char);
        $el.text(type + '|');
        typeIt();

        if (char == txtLen) {
            $el.text($el.text().slice(0, -1)); // remove the '|'
            clearTimeout(timeOut);
        }
    }, humanize);
}())
};

Answer 1

原始代码使用计时器重复操作，直到满足某个条件（递归调用自身）。您已将if支票放在该支票之外，因此它永远不会运行。

在计时器内进行检查，以便反复检查。像这样：

var $el = $('.writer'),
    txt = $el.text(),
    txtLen = txt.length,
    timeOut,
    $topb = $('#topb'),
    char = 0;

$el.text('|');

(function typeIt() {
    if ($topb.hasClass('active')) {
        var humanize = Math.round(Math.random() * (200 - 30)) + 30;
        timeOut = setTimeout(function () {
            char++;
            var type = txt.substring(0, char);
            $el.text(type + '|');
            typeIt();

            if (char == txtLen) {
                $el.text($el.text().slice(0, -1)); // remove the '|'
                clearTimeout(timeOut);
            }
        }, humanize);
    }
    else{
        // do nothing but repeat the timer (e.g. after 2 seconds)
        timeOut = setTimeout(typeIt, 2000);
    }
}());

使jquery函数启动

1 个答案: