JavaScript Basics Chapter 1 JavaScript and Client_Basic Knowledge

One page output
1. Header file

Copy code The code is as follows:

< ;head>

2. Copy the code within the page

The code is as follows:

<script> <br>document.write("Script Home"); <br></script>

3. External file

4. InnerHtml using page ID

Copy code The code is as follows:

<script> <br>window.onload = writeMessage; // Call the writeMessage function when the page is loaded<br>writeMessage( ) { <br>document.getElementById("helloMessage").innerHTML = "Script Home"; <br>//Find the dom ID (helloMessage) and modify its html content<br>} <br></script>

5. Warning
alert("Guangzhou Baihui Logistics Co., Ltd.");
6. Inquiry

Copy code The code is as follows:

if (confirm("Do you want to visit our homepage"))
{
alert("Yes, go to") ;
}
else {
alert("Exit");
}

7. Enter

Copy code The code is as follows:

var ans = prompt("Enter your message","Hello,");
if (ans) {
alert("You said:" ans);
}
else {
alert("Exit, no message");
}

8. Page jump Transfer

Copy code The code is as follows:

<script> <br>window.onload = initAll; <br>function initAll() { <br>document.getElementById("redirect").onclick = initRedirect; <br>} <br>function initRedirect() <br>{ <br>window.location = "index .html"; <br>return false; <br>} <br></script>
Script of Home

9. Judgment branch

Copy code The code is as follows:

<script> <br>window.onload = initAll; <br>function initAll() { <br>document.getElementById("Lincoln").onclick = saySomething; <br>document.getElementById ("Kennedy").onclick = saySomething; <br>document.getElementById("Nixon").onclick = saySomething; <br>} <br>function saySomething() { <br>switch(this.id) { <br>case "Lincoln": <br>alert("Four score and seven years ago..."); <br>break; <br>case "Kennedy": <br>alert("Ask not what your country can do for you..."); <br>break; <br>case "Nixon": <br>alert("I am not a crook!"); <br>break; <br>default: <br>} <br>} <br></script>

type="button" id="Kennedy" value="Kennedy" />
value="Nixon" />

10. Exception catching

Copy code The code is as follows:

window.onload = initAll;
function initAll() {
var ans = prompt("Input parameters: ","");
try {
if (!ans || isNaN(ans) || ans<0) {
throw new Error("The input is not a number");
}
alert("root sign" ans " yes " Math.sqrt(ans));
}
catch (errMsg) {
alert(errMsg.message);
}
}