<TITLE>JS type </title>
<meta http-equiv= "content-type" content= "text/html; Charset=utf-8 ">
<body>
<script type= "text/javascript" >
num is number type
var num = 100;
STR is a string type, note that the string type in JS "or" can be
var str = "haha";
Flag is a Boolean type
var flag = true;
</script>
<script type= "text/javascript" >
Content in multiple script blocks that can be accessed by each other
Alert (flag);
var person = null;
var card;
Alert (card);
Undefined is not a string, it is a type, if you want to determine if a variable is undefined,
Judging by the following code:
if (card = = Undefined) {
Alert ("card variable has no value");
}else{
Alert (card);
}
</script>
There are three ways to define functions in <title>js </title>
<meta http-equiv= "content-type" content= "text/html; Charset=utf-8 ">
<body>
<script type= "text/javascript" >
/* Normal Mode (first)
function Add (num1,num2) {
return NUM1 + num2;
}
Window.alert ("10+20=" + Add (10,20));
*/
</script>
<script type= "text/javascript" >
/* constructor mode, The last parameter is the function body, each parameter is a string type (after)
var add = new Function ("num1", "num2", "return num1+num2");
Window.alert ("100+200=" + Add (100,200));
*/
</script>
<script type= "text/javascript" >
/* Direct volume or anonymous or nameless way (again)
var add = function (num1,num2) {
return NUM1 + num2;
}
Window.alert ("1000+2000=" + Add (1000,2000));
*/
</script>
There are four kinds of objects in <title>js </title>
<meta http-equiv= "content-type" content= "text/html; Charset=utf-8 ">
<body>
<script type= "text/javascript" >
Date
var nowstr = new Date (). tolocalestring ();
Window.document.write (nowstr + "<br/>");
Math
For (var I=1;i<=10;i++) {
Random integers from 1 to 9
document.write (math.floor (math.random () *9) +1 + "<br/>");
//}
String
var str = "hello hi";
var size = str.length;
Alert (SIZE);//7
Array
var array = new array ("language", "math", "english", true,123);
For (var I=0;i<array.length;i++) {
document.write (array[i] + "");
//}
</script>
<script type= "text/javascript" >
/* Custom Objects
function Person (id,name,sal) {
This.id = id;
THIS.name = name;
This.sal = sal;
}
var p = new Person (1, "bobo", 7000);
document.write ("number:" + p.id + "<br/>");
document.write ("name:" + p.name + "<br/>");
document.write ("salary:" + p.sal + "<br/>");
*/
</script>
<script type= "text/javascript" >
Window object, opening new windows
var url = "04_images.html";
window.open (url);
</script>
<script type= "text/javascript" >
Status object, Setting the current time to the status bar
var nowstr = new Date (). tolocalestring ();
Window.status = nowstr;
</script>
<script type= "text/javascript" >
Location object that simulates the user entering a URL in the address bar to access other pages
var url = "04_images.html";
Window.location.href = url;
</script>
<script type= "text/javascript" >
History object, Presentation Refresh
Window.history.go (0);
</script>
<form action= "04_images.html" method= "POST" >
<input type= "button" value= "submit"/>
</form>
<!--demo with JS submission form, important--
<script type= "text/javascript" >
Position Submit button
var inputelement = document.getElementsByTagName ("input") [0];
Add a click event for the Submit button
Inputelement.onclick = function () {
Positioning <form> labeling, forms represents a collection of all forms in a document object, referencing different forms by subscript, starting with 0
var formelement = document.forms[0];
Submit the form to the location specified by the Action property
Formelement.submit ();
}
</script>
JavaScript enhances Ajax Fundamentals
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