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有了非常基本的JavaScript知識,我構建了一個簡單的幻燈片(代碼如下)。它的工作原理,但示出的JSLint以下錯誤:JSLint錯誤:未聲明的'圖像',未聲明的'文檔',超出範圍
- 未聲明的 '圖像' slideimages [0] =新的圖像();
- 未聲明'setInterval' setInterval(myCounter,50);
- 'myCounter'超出範圍 setInterval(myCounter,50);
- 未聲明'文檔' document.getElementById('slide')。src = slideimages [step] .src;
我該如何解決這些問題,例如宣佈這些元素?
var slideimages = [];
slideimages[0] = new Image();
slideimages[0].src = "http://placehold.it/350x150?text=Welcome";
slideimages[1] = new Image();
slideimages[1].src = "imgs/slide_1.png";
slideimages[2] = new Image();
slideimages[2].src = "imgs/slide_2.png";
var step = 0;
var c = 0;
var a = 0;
setInterval(myCounter, 50);
function myCounter() {
'use strict';
document.getElementById('slide').src = slideimages[step].src;
if ((c >= 0) && (c < 40)) {
c += 1;
a = c;
step = 1;
document.getElementById("demo").innerHTML = a/100;
document.getElementById("slide").style.opacity = a/40;
} else if ((c >= 40) && (c < 80)) {
c += 1;
a = c;
document.getElementById("demo").innerHTML = a/100;
document.getElementById("slide").style.opacity = 1;
} else if ((c >= 80) && (c < 100)) {
c += 1;
a = c;
document.getElementById("demo").innerHTML = 1 - ((a - 80)/20);
document.getElementById("slide").style.opacity = 1 - ((a - 80)/20);
} else if ((c >= 100) && (c < 140)) {
c += 1;
a = c;
step = 2;
document.getElementById("demo").innerHTML = a/100;
document.getElementById("slide").style.opacity = (a - 100)/40;
} else if ((c >= 140) && (c < 180)) {
c += 1;
a = c;
document.getElementById("demo").innerHTML = a/100;
document.getElementById("slide").style.opacity = 1;
} else if ((c >= 180) && (c < 200)) {
c += 1;
a = c;
document.getElementById("demo").innerHTML = 1 - ((a - 180)/20);
document.getElementById("slide").style.opacity = 1 - ((a - 180)/20);
} else {
c = 0;
}
}