[英]How to check table for new content, and then update browser tab title?
當表格中出現新消息時,我正在設法刷新瀏覽器標簽。 我的選項卡部分正在閃爍,我唯一的問題是,收到消息后,似乎無法使其閃爍(這是我練習的全部要點:))
newMessage()
函數工作正常,我似乎無法使notification()
函數正常工作。
我的代碼如下:
function newMessage()
{
var oldTitle = "Your Page";
var msg = "New Message";
var timeout = setInterval(function()
{
document.title = document.title == msg ? '' : msg;
}, 1000);
window.onmousemove = function() {
clearInterval(timeout);
document.title = oldTitle;
window.onmousemove = null;
};
}
function notification()
{
var index = 2;
var content = document.getElementById('refreshMessages').childNodes[index];
var content = document.getElementById('refreshMessages').getElementByTagName("tr")[1];
var knownContent = content.toString();
updater.start();
updater2.start();
var newContent = document.getElementById('refreshMessages').childNodes[index];
var newContent = document.getElementById('refreshMessages').getElementByTagName("tr")[1];
if(knownContent != newContent.toString())
{
newMessage();
knownContent = newContent;
}
else if(knownContent = newContent.toString())
{
alert("No need to flash title.");
}
}
notification();
在notification()
函數中,我試圖通過比較表中適當單元格處的字符串來調用newMessage()
函數。
我將alert()
放到else中,只是為了查看它是否會被調用,但不會發生。 但是,執行update.start()
和update2.start()
過程如我所見,該消息出現在表中。
我會更高興使用JavaScript,但我也對jQuery開放。
我的JavaScript非常生銹,如果我犯了任何愚蠢的錯誤,請原諒!
謝謝,
卡盤
您在函數notification()中有幾個錯誤,請參閱我的評論:
function notification()
{
var index = 2;
//Why are you assigning value to "content" for twice?
var content = document.getElementById('refreshMessages').childNodes[index];
/*
* function getElementByTagName is undefined, should be getElementsByTagName,
* 's' is missing. And [1] means the second one not the first one, make sure
* that's exactly what you want.
*/
var content = document.getElementById('refreshMessages').getElementByTagName("tr")[1];
/*
* content is a tr dom object, content.toString() is something like "[object]".
* If you want to get content inside a cell, you should use cell.innerHTML.
* e.g. A table:
* <table id="refreshMessages">
* <tr><td>Hello world</td></tr>
* </table>
* var table = document.getElementById('refreshMessages');
* var firstTr = table.getElementsByTagName("tr")[0];
* var firstTd = firstTr.getElementsByTagName("td")[0];
* alert(firstTd.innerHTML); //alerts "Hello world"
*/
var knownContent = content.toString();
//I doubt these functions really get invoked cuz there's javascript error above.
updater.start();
updater2.start();
//assigning twice, "getElementByTagName" is missing "s"
var newContent = document.getElementById('refreshMessages').childNodes[index];
var newContent = document.getElementById('refreshMessages').getElementByTagName("tr")[1];
//Remove toString(), use innerHTML i metioned above.
if(knownContent != newContent.toString())
{
newMessage();
knownContent = newContent;
}
//You miss an "=" here, to judge a equals b, you should use "=="
else if(knownContent = newContent.toString())
{
alert("No need to flash title.");
}
}
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