http://www.w3schools.com/js/
uses of js
inject dynamic text into a web page (document.write)
validate data
respond to events
detect browser
cookies
putting a js script into a page
link
if in head, called when executed by an event
if in body, called when page is loaded
variables
var strname = some value
or
strname = value
local vs. global variables
operators + - * / % ++ -- = += -= *= /= %= == != > < >= <= && || ! (same)
+ concatenates Strings (same)
=== checks for equal value AND type (== just checks value; 5 and "5" would be equal)
strings
escape characters with \ (same) \' \" \& \\ \n \t
.length
.toUpperCase()
http://www.w3schools.com/js/js_obj_string.asp
if, if/else, nested if/else (same)
if (condition1)
{
code to be executed if condition1 is true
}
else if (condition2)
{
code to be executed if condition2 is true
}
else
{
code to be executed if condition1 and
condition2 are not true
}
message boxes
alert("text")
varname = prompt("message", "defaultvalue")
if (confirm("text")) { ... }
for (var=startvalue;var<=endvalue;var=var+increment)
{
code to be executed
}
while (test)
{
code to be executed
}
do
{
code to be executed
}
while (test)
break, continue (same)
// foreach loop
for (variable in object)
{
code to be executed
}
comments: // /* */
functions
function functionname(param1,param2,...,paramX)
{
some code
}
events
http://www.w3schools.com/js/js_events.asp
onload, onUnload, onfocus, onblur, onchange, onsubmit, onMouseOver, onMouseOut, onError
onerror event