<head> </head> <body> <!-- The onclick attribute is the code that happens when the element is clicked. The value of the attribute is some javascript code. In this case it creates an alert pop up dialog --> <h1 id="title" onclick="alert('hello');" > Hello </h1> </body>
<head> </head> <body> <!-- In this case the onclick functions writes something to the console. The console is an object so we use the dot (.) notation to call a function on it --> <h1 id="title" onclick="console.log('hello');" > Hello </h1> </body>
I don't know does the code " console.log('hello') " whether means make a object(console) do sth.?
2.How to use the jQuery
<head> <!-- to use jQuery we need to import it like this --> <script src=" http://code.jquery.com/jquery-1.11.3.min.js"></script> </head> <body> <!-- in this example use use jQuery to change the content itself. The $ is shorthand for the jQuery function We are passing in a CSS selector which gets this element by its id. The html function sets the html content of an element --> <h1 id="title" onclick="$('#title').html('Goodbye');"> Hello </h1> </body>
3.How to define a function in javaScript
<head> <script src = "http://code.jquery.com/jquery-1.11.3.min.js"></script> </head> <body> <h1 id="title" onclick="sayHello()"> Hello </h1> </body> <!-- the script tag is where you can put more complex scripts --> <script type="text/javascript"> function sayHello() { alert('Hello'); }; </script>