Practical application code analysis of JS parameter passing_javascript skills

The reason is very simple. There is no div tag with the id msg_box in the DOM. How to solve this problem?
Solution:
Write in the header file header.tpl.html common to all pages:

Copy code The code is as follows:

<script> <BR>function changMenu(index){ <BR>if(typeof getElementById("msg_box") == "object"){ <BR>// If the msg_box object exists, refresh the object of the page <BR>showMenu(index); <BR>}else{ <BR>//If it does not exist, redirect to the page refreshed using Ajax <BR>window.location = "/ index.html"; <BR>} <BR>} <BR></script>

However, the project index.html has four pages of the same nature, all of which require Ajax to refresh. There is a problem. When the user clicks on the third column, although he can return to index.html, he cannot refresh the content to the third column. There are two solutions at this time:
Option 1:
Step 1:
Write in the header file header.tpl.html common to all pages:

Copy code The code is as follows:

<script> <BR>function changMenu(index){ <BR>if(typeof getElementById( "msg_box") == "object"){ <BR>//If the msg_box object exists, refresh the object of the page <BR>showMenu(index); <BR>}else{ <BR>//Refresh if it does not exist Direct to page refreshed using Ajax <BR>window.location = "/index.html?type=" index; <BR>} <BR>} <BR></script>

Step 2:
Improve showMenu function

Copy code The code is as follows:

function showMenu (index){
if(typeof getElementById("msg_box") == "object"){
//If the msg_box object exists, refresh the object of the page
......
}else{
url = window.location.href;
reg = /^(.*)/index.html?type=d$/gi;
if(reg.test(url)){
//If it matches the url of the parameter page. Then get the parameter
index = url.substr(url.length - 1);
......
}
}
}

Option 2:
Call the cookie function of JS to pass parameters
Write in the header file header.tpl.html common to all pages:

Copy the code The code is as follows:

<script> <BR>function changMenu(){ <BR>index = getCookie("index"); <BR>if( index == null) index = 1; <BR>if(typeof getElementById("msg_box") == "object"){ <BR>//If the msg_box object exists, refresh the object of the page <BR>showMenu(index) ; <BR>}else{ <BR>setCookie("index", index); <BR>//If it does not exist, redirect to the page refreshed using Ajax <BR>window.location = "/index.html"; <BR>} <BR>} <BR>function setCookie(name, value){　 <BR>　var Then = new Date()　 <BR>　Then.setTime(Then.getTime() 1*3600000) //Hour<BR>Document.cookie = name "=" value ";expires=" Then.toGMTString();　 <BR>} <BR>function getCookie(name) <BR>{ <BR>var arr = document.cookie.match(new RegExp("(^| )" name "=([^;]*)(;|$)")); <BR>if(arr != null) return unescape(arr[2]); return null; <BR>} <BR>　 <BR></script>