Countdown var to loop and display array
I'm very new to javascript and I'm trying to do something I thought would be very basic.
I've created a countdown timer and used "i" as my variable to hold a number from 0-5. And I have an array of "d" from d[0] to d[5] containing strings.
I'm trying to make the timer countdown pass the "i" value into an innerHTML method array value so I want it to display d[5]... d[4]...开发者_高级运维d[3]... etc.
What am I doing wrong!? Please Help!
<html><head><script language="javascript" type="text/javascript">
var d=new Array():
d[1]="One";
d[2]="Two";
d[3]="Three";
d[4]="Four";
d[5]="Five";
var i=5;
var i=setInterval("timer()",2000); //1000 will run it every 1 second
function timer() {
i--;
if (i <= 0)
clearInterval(countD);
return;
}
}
document.getElementById(timer).innerHTML = d[i];
</script>
</head>
<body>
<h1>
<p id="timer"></p>
</h1>
</body>
</html>
Also, document.getElementById(timer).innerHTML = d[i];
should be document.getElementById("timer").innerHTML = d[i];
id names need to have quotes around them because they are not names of variables. The variable 'timer' is undefined.
Also, you are missing a curly brace on the line if (i <= 0). I am assuming that you meant to exit the function if this if statement is true.
Also, you have a colon instead of a semicolon on the line var d=new Array():
Also, you can't have a paragraph tag inside of an h1
Also, you should encapsulate all of this javascript into a function called something like init. I believe that the javascript code in the head runs before the html is loaded. The javascript can't therefore find the
tag. Then, use <body onload="init()"> as your body tag.
EDIT: As the commenters have stated, you are using the variable i for multiple unrelated things.
I'm sorry to say but your code is quite a mess; here's one way to get your code to work, along with a working example:
<html>
<head>
<script language="javascript" type="text/javascript">
var d=new Array();
d[0]="One";
d[1]="Two";
d[2]="Three";
d[3]="Four";
d[4]="Five";
var i=4;
var myTimer =setInterval(timer,2000); //1000 will run it every 1 second
function timer() {
document.getElementById("timer").innerHTML = d[i];
i--;
if (i < 0){
clearInterval(myTimer);
}
}
</script>
</head>
<body>
<h1>
<p id="timer"></p>
</h1>
</body>
</html>
The problems with your JavaScript
- You've got two declarations for
i, one after the other - one is set to5and the other to thesetIntervaltimer - What is
countDinclearInterval(countD);? document.getElementById(timer).innerHTML = d[i];is attempting to use the functiontimeras the argument togetElementById. It should be in quotes:document.getElementById("timer").innerHTML = d[i];- It is also being invoked only once since it's not inside the function that is being called by the timer.
var d=new Array():should be terminated by a;(semi-colon) and not a:(colon)- You have unmatched braces - your
ifstatement doesn't have an opening brace ({) but it does have a closing one. - Note that while
setInterval("timer()", 1000)is valid JavaScript, it depends onevalwhich should be avoided if possible. The alternate, preferred way to use this issetInterval(timer, 1000)i.e. passing the function and not a string.
加载中,请稍侯......
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