Đang tải... (xem toàn văn)
Thực hành Java Script
<html><body><script type="text/javascript">{document.write("<h1>This is a heading</h1>");document.write("<p>This is a paragraph.</p>");document.write("<p>This is another paragraph.</p>");}</script></body></html>JavaScript Popup Boxes<html><head><script type="text/javascript">function show_alert(){alert("I am an alert box!");}</script></head><body><input type="button" onclick="show_alert()" value="Show alert box" /></body></html><html><head><script type="text/javascript">function disp_alert(){alert("Hello again! This is how we" + '\n' + "add line breaks to an alert box!");}</script></head><body><input type="button" onclick="disp_alert()" value="Display alert box" /></body></html>1 <head><script type="text/javascript">function show_confirm(){var r=confirm("Press a button");if (r==true) { document.write("You pressed OK!"); }else { document.write("You pressed Cancel!"); }}</script></head><body><input type="button" onclick="show_confirm()" value="Show a confirm box" /></body></html>Function<html> <head> <script type="text/javascript"> function myfunction(txt) { alert(txt);} </script> </head> <body> <form action= “dia chi trang web”method= “GET”> <input type="button" onclick="myfunction('Good Morning!')" value="In the Morning"> <input type="button" onclick="myfunction('Good Evening!')" value="In the Evening"> </form> <p>When you click on one of the buttons, a function will be called. The function will alertthe argument that is passed to it.</p></body> </html> 2 Event ObjectWhich mouse button was clicked?<html><head><script type="text/javascript">function whichButton(event){if (event.button==2) { alert("You clicked the right mouse button!"); }else { alert("You clicked the left mouse button!"); }}</script></head><body onmousedown="whichButton(event)"><p>Click in the document. An alert box will alert which mouse button you clicked.</p></body></html>What is the keycode of the key pressed?<html><head><script type="text/javascript">function whichButton(event){alert(event.keyCode);}</script></head><body onkeyup="whichButton(event)"><p><b>Note:</b> Make sure the right frame has focus when trying this example!</p><p>Press a key on your keyboard. An alert box will alert the keycode of the key.</p></body></html>What are the coordinates of the cursor?<html><head><script type="text/javascript">function show_coords(event){x=event.clientX;y=event.clientY;3 alert("X coords: " + x + ", Y coords: " + y);}</script></head><body onmousedown="show_coords(event)"><p>Click in the document. An alert box will alert the x and y coordinates of the mouse pointer.</p></body></html>View and change the action URL of a form<html><head><script type="text/javascript">function changeAction(){var x=document.getElementById("myForm");alert("Original action: " + x.action);x.action="default.asp";alert("New action: " + x.action);x.submit();}</script></head><body><form id="myForm" action="js_examples.asp">Name: <input type="text" name=”t1” value="Mickey Mouse" /><input type="button" onclick="changeAction()"value="Change action attribute and submit form" /></form></body></html>View the method that is to be used when sending form data<html>4 <head><script type="text/javascript">function showMethod(){var x=document.getElementById("myForm");alert(x.method);}</script></head><body><form id="myForm" method="post">Name: <input type="text" size="20" value="Mickey Mouse" /><input type="button" onclick="showMethod()" value="Show method" /></form></body></html>Alert id, type, and value of a Button object + disable button<html><head><script type="text/javascript">function alertId(){var txt="Id: " + document.getElementById("myButton").id;txt=txt + ", type: " + document.getElementById("myButton").type;txt=txt + ", value: " + document.getElementById("myButton").value;alert(txt);document.getElementById("myButton").disabled=true;}</script></head><body><form name=“f1”><input type="button" value="Click me!" id="myButton" onclick="alertId()" /></form></body></html>Check and uncheck a checkbox<html><head>5 <script type="text/javascript">function check(){//document.getElementById("myCheck").checked=true;document.f1.uncheck.checked=true;}function uncheck(){//document.getElementById("myCheck").checked=false;document.f1.check.checked=false;}</script></head><body><form name= “f1”><input type="checkbox" id="myCheck" /><input type="button" onclick="check()" value="Check Checkbox" name= “check”/><input type="button" onclick="uncheck()" value="Uncheck Checkbox" name= “uncheck”/></form></body></html>Checkboxes in a form<html><head><script type="text/javascript">function createOrder(){coffee=document.forms[0].coffee;txt="";for (i=0;i<coffee.length;++ i) { if (coffee[i].checked!=0) { txt=txt + coffee[i].value + " "; } }document.getElementById("order").value="You ordered a coffee with " + txt;}</script></head><body><p>How would you like your coffee?</p><form><input type="checkbox" name="coffee" value="cream">With cream<br /><input type="checkbox" name="coffee" value="sugar">With sugar<br />6 <br /><input type="button" onclick="createOrder()" value="Send order"><br /><br /><input type="text" id="order" size="50"></form></body></html>Checkbox<html><head><script type="text/javascript">function convertToUcase(){document.getElementById("fname").value=document.getElementById("fname").value.toUpperCase();document.getElementById("lname").value=document.getElementById("lname").value.toUpperCase();}</script></head><body><form name="form1">First name: <input type="text" id="fname" size="20" /><br /><br />Last name: <input type="text" id="lname" size="20" /><br /><br />Convert to upper case <input type="checkBox" onclick="if (this.checked) {convertToUcase()}"></form></body></html>Radio buttons<html><head><script type="text/javascript">function check(browser) { document.getElementById("answer").value=browser; }</script></head><body><p>What's your favorite browser?</p><form>7 <input type="radio" name="browser" onclick="check(this.value)" value="Internet Explorer">Internet Explorer<br /><input type="radio" name="browser" onclick="check(this.value)" value="Firefox">Firefox<br /><input type="radio" name="browser" onclick="check(this.value)" value="Netscape">Netscape<br /><input type="radio" name="browser" onclick="check(this.value)" value="Opera">Opera<br /><br />Your favorite browser is: <input type="text" id="answer" size="20"></form></body></html>Reset a form<html><head><script type="text/javascript">function formReset(){document.getElementById("myForm").reset();}</script></head><body><p>Enter some text in the text fields below, and then press the "Reset" button to reset the form.</p><form id="myForm">Name: <input type="text" size="20"><br />Age: <input type="text" size="20"><br /><br /><input type="button" onclick="formReset()" value="Reset"></form></body></html>Submit a form<html><head><script type="text/javascript">function formSubmit(){document.getElementById("myForm").submit();}</script></head><body><p>Enter some text in the text fields below, and then press the "Submit" button to submit the form.</p><form id="myForm" action="js_form_action.asp" method="get">8 Firstname: <input type="text" name="firstname" size="20"><br />Lastname: <input type="text" name="lastname" size="20"><br /><br /><input type="button" onclick="formSubmit()" value="Submit"></form></body></html>Form validation<html><head><script type="text/javascript">function validate(){var at=document.getElementById("email").value.indexOf("@");var age=document.getElementById("age").value;var fname=document.getElementById("fname").value;submitOK="true";if (fname.length>10) { alert("The name may have no more than 10 characters"); submitOK="false"; }if (isNaN(age)||age<1||age>100) { alert("The age must be a number between 1 and 100"); submitOK="false"; }if (at==-1) { alert("Not a valid e-mail!"); submitOK="false"; }if (submitOK=="false") { return false; }}</script></head><body><form action="tryjs_submitpage.htm" onsubmit="return validate()">Name (max 10 characters): <input type="text" id="fname" size="20"><br />Age (from 1 to 100): <input type="text" id="age" size="20"><br />E-mail: <input type="text" id="email" size="20"><br /><br /><input type="submit" value="Submit"> </form>9 </body></html>Set focus to an input field when the page loads<html><head><script type="text/javascript">function setFocus(){document.getElementById("fname").focus();}</script></head><body onload="setFocus()"><form>Name: <input type="text" id="fname" size="30"><br />Age: <input type="text" id="age" size="30"> </form></body></html>Select the content of an input field<html><head><script type="text/javascript">function selText(){document.getElementById("myText").select();}</script></head><body><form><input size="25" type="text" id="myText" value="A cat played with a ball"><input type="button" value="Select text" onclick="selText()"> </form></body></html>10 [...]... paragraph.</p>"); } < /script& gt; </body> </html> JavaScript Popup Boxes <html> <head> < ;script type="text/javascript"> function show_alert() { alert("I am an alert box!"); } < /script& gt; </head> <body> <input type="button" onclick="show_alert()" value="Show alert box" /> </body> </html> <html> <head> < ;script type="text/javascript"> function... /> </form> 13 < ;script type="text/javascript"> document.write(document.getElementById("mySelect").form.id); < /script& gt; </p> </body> </html> Get the number of options in the dropdown list <html> <head> < ;script type="text/javascript"> function getLength() { alert(document.getElementById("mySelect").length); } < /script& gt; </head> <body> <form> <select... list <html> <head> < ;script type="text/javascript"> function getOptions() { var x=document.getElementById("mySelect"); txt="All options: " for (i=0;i<x.length;i++) { txt=txt + "\n" + x.options[i].text; } alert(txt); } < /script& gt; </head> <body> <form> 16 < ;script type="text/javascript"> function check() { //document.getElementById("myCheck").checked=true; document.f1.uncheck.checked=true; } function... event <html> <head> < ;script type="text/javascript"> function startTime() { var today=new Date(); 18 <html> <body> < ;script type="text/javascript"> { document.write("<h1>This is a heading</h1>"); document.write("<p>This is a paragraph.</p>"); document.write("<p>This is another paragraph.</p>"); } < /script& gt; </body> </html> JavaScript... list <html> <head> < ;script type="text/javascript"> function changeSize() { document.getElementById("mySelect").size=4; } < /script& gt; </head> <body> <form> <select id="mySelect"> <option>Apple</option> <option>Banana</option> <option>Orange</option> <option>Melon</option> 15 <head> < ;script type="text/javascript"> function... form <html> <head> < ;script type="text/javascript"> function createOrder() { coffee=document.forms[0].coffee; txt=""; for (i=0;i<coffee.length;++ i) { if (coffee[i].checked!=0) { txt=txt + coffee[i].value + " "; } } document.getElementById("order").value="You ordered a coffee with " + txt; } < /script& gt; </head> <body> <p>How... /> 6 Event Object Which mouse button was clicked? <html> <head> < ;script type="text/javascript"> function whichButton(event) { if (event.button==2) { alert("You clicked the right mouse button!"); } else { alert("You clicked the left mouse button!"); } } < /script& gt; </head> <body onmousedown="whichButton(event)"> <p>Click... will alert which mouse button you clicked.</p> </body> </html> What is the keycode of the key pressed? <html> <head> < ;script type="text/javascript"> function whichButton(event) { alert(event.keyCode); } < /script& gt; </head> <body onkeyup="whichButton(event)"> <p><b>Note:</b> Make sure the right frame has focus when... size"> </form> </body> </html> Select multiple options in a dropdown list <html> <head> < ;script type="text/javascript"> function selectMultiple() { document.getElementById("mySelect").multiple=true; } < /script& gt; </head> <body> <form> <select id="mySelect" size="4"> <option>Apple</option> <option>Pear</option> <option>Banana</option> <option>Orange</option> </select> <input... option"> </form> </body> </html> Remove options from a dropdown list <html> <head> < ;script type="text/javascript"> function removeOption() { var x=document.getElementById("mySelect"); x.remove(x.selectedIndex); } < /script& gt; </head> <body> <form> <select id="mySelect"> <option>Apple</option> . paragraph.</p>");}< /script& gt;</body></html>JavaScript Popup Boxes<html><head>< ;script type="text/javascript">function. /></body></html>Function<html> <head> < ;script type="text/javascript"> function myfunction(txt) { alert(txt);} < /script& gt; </head> <body>