我正在尝试将文字选框放入我的网站。一切正常,除了文本在鼠标滚动之前不会开始滚动。我需要它在页面加载时开始滚动。
相同的代码在这里开始onload:http://javascript.about.com/library/blctmarquee1.htm
我的控制台说:
Uncaught TypeError: Cannot call method 'getElementsByTagName' of null mq Marquee_Testing.html:61 start Marquee_Testing.html:41
这是javascript:
function start() {
new mq('m1');
new mq('m2');
mqRotate(mqr); // must come last
}
window.onload = start;
function objWidth(obj) {
if (obj.offsetWidth) return obj.offsetWidth;
if (obj.clip) return obj.clip.width;
return 0;
}
var mqr = [];
function mq(id) {
this.mqo = document.getElementById(id);
var wid = objWidth(this.mqo.getElementsByTagName('span')[0]) + 5;
var fulwid = objWidth(this.mqo);
var txt = this.mqo.getElementsByTagName('span')[0].innerHTML;
this.mqo.innerHTML = '';
var heit = this.mqo.style.height;
this.mqo.onmouseout = function () {
mqRotate(mqr);
};
this.mqo.onmouseover = function () {
clearTimeout(mqr[0].TO);
};
this.mqo.ary = [];
var maxw = Math.ceil(fulwid / wid) + 1;
for (var i = 0; i < maxw; i++) {
this.mqo.ary[i] = document.createElement('div');
this.mqo.ary[i].innerHTML = txt;
this.mqo.ary[i].style.position = 'absolute';
this.mqo.ary[i].style.left = (wid * i) + 'px';
this.mqo.ary[i].style.width = wid + 'px';
this.mqo.ary[i].style.height = heit;
this.mqo.appendChild(this.mqo.ary[i]);
}
mqr.push(this.mqo);
}
function mqRotate(mqr) {
if (!mqr) return;
for (var j = mqr.length - 1; j > -1; j--) {
maxa = mqr[j].ary.length;
for (var i = 0; i < maxa; i++) {
var x = mqr[j].ary[i].style;
x.left = (parseInt(x.left, 10) - 1) + 'px';
}
var y = mqr[j].ary[0].style;
if (parseInt(y.left, 10) + parseInt(y.width, 10) < 0) {
var z = mqr[j].ary.shift();
z.style.left = (parseInt(z.style.left) + parseInt(z.style.width) * maxa) + 'px';
mqr[j].ary.push(z);
}
}
mqr[0].TO = setTimeout('mqRotate(mqr)', 10);
}
答案 0 :(得分:0)
我通过删除
来修复此问题new mq('m2');
我仍然不知道为什么这会影响marquee'm1'滚动onload的能力,但它在任何情况下都已解决。