CS174
Chris Pollett
Oct 31, 2016
We now want to consider adding dynamic behaviors to our websites as they are interacted with on the client-side. To do this, we will use the Javascript language.
Which of the following statements is true?
git commit < name_of_patch.txt
Which of the following statements is true?
git am --signoff < name_of_patch.txt
<script type="text/javascript"> -- code -- </script>
<script type="text/javascript" src="myscript.js" />
return x; // has the effect of just return!
<html> <head><title>test</title> <meta name="description" value="this example illustrates how Javascripts are executed both when the document is loaded and on the occurrence of events" /> <script type="text/javascript" > function sayHello() { alert("hi there"); } </script> </head><body><form><input type="button" value="test" onclick="return sayHello();" /><!-- responds to events --></form> <script type="text/javascript" > for( i = 0; i<100; i++) { document.writeln("<p>hi"+i+"</p>"); } // run when document loads </script></body> </html>
var my_variable, pi=3.14; // explicit declarations effect the scope of the variable
first = "hello" second = first + "bye" // "hellobye"
"August" + 1977 // "August1977" 1977 + "August" // "1977August" 7*"3" =21
var str_value = String(value); // Might want to use toString var some_number = Number(some_string); // Might want to use parseInt or parseFloat
typeof x //and typeof(x)returns either "boolean", "string", "number" if x is of primitive type, it returns "object" if x is null or an object; and it returns "undefined" if x is not defined.
a++; a+=2; a--; a-=2; a = b +57;
var today = new Date();
name = prompt("What is your name", "John Smith")
var my_object = new Object();
delete my_object;
my_object.make= "V6" /* would then give a property make a value. */ //can access as p = my_object["make"] q = my_object.make //to delete a property of an object we can do delete my_object.make
my_object.subObject = new Object();
for (prop in my_object) { alert("prop:" + prop + "\nvalue:" + my_object[prop]); }
my_object = { make: "V6", subObject: {} }
my_object.hasOwnProperty("make"); //returns true given object above
var myArr = new Array(1, 2, "hello") var myArr = new Array(100); var myArr = [1,2,3]; //to access myArr[0] //to determine length myArr.length
var names = new Array("Mary", "Murray", "Max"); var nstring = names.join(":");
var a = [1, 2, 3]; a.concat(4, 5);