JS Common Function Usage Guide_Basic Knowledge

1.document.write(""); Output statement

2. The comment in JS is //

3. The traditional order of HTML documents is: document->html->(head,body)

4. The DOM sequence in a browser window is: window->(navigator, screen, history, location, document)

5. Get the name and value of the element in the form: document.getElementById("ID number of the element in the form").name (or value)

6. A JS that converts lowercase to uppercase: document.getElementById("output").value = document.getElementById("input").value.toUpperCase();

7. Value types in JS: String, Number, Boolean, Null, Object, Function

8. Convert character type to numeric type in JS: parseInt(), parseFloat()

9. Convert numbers in JS to character type: ("" variable)

10. The length of string in JS is: (length)

11.Characters in JS are connected with characters using numbers.

12. The comparison operators in JS are: == equal to, != not equal to, >, >=, <.<=

13. Use: var to declare variables in JS

14. Judgment statement structure in JS: if(condition){}else{}

15. Loop structure in JS: for([initial expression];[condition];[upadte expression]) {inside loop}

16. The command to terminate the loop is: break

17. Function definition in JS: function functionName([parameter],...){statement[s]}

18. When multiple forms appear in the file, you can use document.forms[0], document.forms[1] instead.

19. Window: open window window.open(), close a window: window.close(), window itself: self

20. Status bar settings: window.status="character";

21. Pop-up prompt message: window.alert("Character");

22. Pop up confirmation box: window.confirm();

23. Pop up the input prompt box: window.prompt();

24. Specify the location of the currently displayed link: window.location.href="URL"

25. Get the number of all forms in the form: document.forms.length

26. Close the document’s output stream: document.close();

27. String append concatenation: =

28. Create a document element: document.createElement(), document.createTextNode()

29. Method to get elements: document.getElementById()

30. Set the value of all text members in the form to be empty:

var form = window.document.forms[0]

for (var i = 0; i

if (form.elements[i].type == "text"){

form.elements[i].value = "";

}

}

31. Determine whether the check button is checked in JS: document.forms[0].checkThis.checked (the checked attribute represents whether it is selected and returns TRUE or FALSE)

32. Radio button group (the names of the radio buttons must be the same): take the length of the radio button group document.forms[0].groupName.length

33. The radio button group also uses checked to determine whether it is selected.

34. The value of the drop-down list box: document.forms[0].selectName.options[n].value (n sometimes uses the name of the drop-down list box plus .selectedIndex to determine the selected value)

35. Definition of string: var myString = new String("This is lightsword");

36. Convert a string to uppercase: string.toUpperCase(); Convert a string to lowercase: string.toLowerCase();

37. Return the position where string 2 appears in string 1: String1.indexOf("String2")!=-1 means it was not found.

38. Get a character at the specified position in the string: StringA.charAt(9);

39. Take out the substring with specified starting point and end point in the string: stringA.substring(2,6);

40. Mathematical functions: Math.PI (returns pi), Math.SQRT2 (returns square root), Math.max(value1, value2) returns the greatest value of two numbers, Math.pow(value1,10 ) returns the tenth power of value1, Math.round(value1) rounding function, Math.floor(Math.random()*(n 1)) returns a random number

41. Define date variables: var today = new Date();

42. List of date functions: dateObj.getTime() gets the time, dateObj.getYear() gets the year, dateObj.getFullYear() gets the four-digit year, dateObj.getMonth() gets the month, dateObj.getDate() gets

Day, dateObj.getDay() gets the date, dateObj.getHours() gets the hours, dateObj.getMinutes() gets the minutes, dateObj.getSeconds() gets the seconds, dateObj.setTime(value) sets the time, dateObj.setYear (val) sets the year, dateObj.setMonth(val) sets the month, dateObj.setDate(val) sets the day, dateObj.setDay(val) sets the day of the week, dateObj.setHours sets the hours, dateObj.setMinutes(val) sets the minutes, dateObj .setSeconds(val) sets seconds [Note: This date and time starts from 0]

43.FRAME representation: [window.]frames[n].ObjFuncVarName,frames["frameName"].ObjFuncVarName,frameName.ObjFuncVarName

44.parent represents the parent object, and top represents the top object

45. The parent window that opens the child window is: opener

46. Indicates the current location: this

47. When calling a JS function in a hyperlink, use: (javascript:) to start with the function name

48. Do not execute this JS in old browsers:

49. Quote a file-style JS:

50. Specify HTML to be displayed in browsers that do not support scripts:

51. When there are both hyperlinks and ONCLICK events, the old version of the browser will redirect to a.html, otherwise it will redirect to b.html. Example: dfsadf

52. The built-in objects of JS are: Array, Boolean, Date, Error, EvalError, Function, Math, Number, Object, RangeError, ReferenceError, RegExp, String, SyntaxError, TypeError, URIError

53. Line breaks in JS:n

54. Window full screen size:<script>function fullScreen(){ this.moveTo(0,0);this.outerWidth=screen.availWidth;this.outerHeight=screen.availHeight;}</p> <p>window.maximize=fullScreen;</script>

55.all in JS represents all the elements below it

56.Focus order in JS: document.getElementByid("Form Element").tabIndex = 1

57. The value of innerHTML is the value of the form element: such as

"how are you"

, then the value of innerHTML is: how are you

58.The value of innerTEXT is the same as above, except that tags like will not be displayed.

59.contentEditable can set whether the element can be modified, and isContentEditable returns whether the element can be modified.

60.isDisabled determines whether it is a prohibited state. disabled sets the prohibited state

61.length gets the length and returns an integer value

62.addBehavior() is an external function file called by JS. Its extension is .htc

63.window.focus() puts the current window in front of all windows.

64.blur() means losing focus. It is the opposite of FOCUS().

65.select() means that the element is selected.

66. Prevent users from entering text into the text box:

67. Get the number of occurrences of this element on the page: document.all.tags("div (or other HTML tags)").length

68.JS is divided into two types of form output: modal and non-modal.window.showModaldialog(), window.showModeless()

69. Status bar text setting: window.status='text', default status bar text setting: window.defaultStatus = 'text.';

70. Add to favorites: external.AddFavorite("http://www.xrss.cn","jaskdlf");

71. No action is taken when a script error is encountered in JS: window.onerror = doNothing; The syntax for specifying an error handle is: window.onerror = handleError;

72. Specify the parent window of the currently opened window in JS: window.opener, and support multiple continuations of opener.opener...

73.Self in JS refers to the current window

74. The content displayed in the status bar in JS: window.status="content"

75. The top in JS refers to the topmost frame in the frame set

76. Close the current window in JS: window.close();

77. Confirmation box in JS: if(confirm("Are you sure?")){alert("ok");}else{alert("Not Ok");}

78.Window redirection in JS: window.navigate("http://www.sina.com.cn");

79. Printing in JS: window.print()

Prompt input box in 80.JS: window.prompt("message","defaultReply");

Window scroll bar in 81.JS: window.scroll(x,y)

82.Scroll the window to the position in JS: window.scrollby

83. Set time interval in JS: setInterval("expr",msecDelay) or setInterval(funcRef,msecDelay) or setTimeout

84. The modal display in IE4 in JS does not work in NN: showModalDialog("URL"[,arguments][,features]);

85. The handle used before exiting in JS: function verifyClose(){event.returnValue="we really like you and hope you will stay longer.";}} window.onbeforeunload=verifyClose;

86. The file handle used when the form is called for the first time: onload()

87. File handle called when the form is closed: onunload()

Attributes of 88.window.location: protocol(http:),hostname(www.example.com),port(80),host(www.example.com:80),pathname("/a /a.html"), hash("#giantGizmo", refers to jumping to the corresponding anchor), href (all information)

89.window.location.reload() refreshes the current page.

89-1.parent.location.reload() refreshes the parent object (for frames)

89-2.opener.location.reload() refreshes the parent window object (for single-open window)

89-3.top.location.reload() refreshes the top object (for multiple windows)

90.window.history.back() returns to the previous page, window.history.forward() returns to the next page, window.history.go (return to which page, you can also use the visited URL)

91.document.write() output without line breaks, document.writeln() output with line breaks

92.document.body.noWrap=true; prevent link text from wrapping.

93. Variable name.charAt(number), get the character of the variable.

94."abc".charCodeAt(number), returns the ASCii code value of which character.

95. String concatenation: string.concat(string2), or use = to connect

96. Variable.indexOf("Character", starting position), returns the first appearing position (calculated from 0)

97.string.lastIndexOf(searchString[,startIndex]) The last occurrence position.

98.string.match(regExpression), determine whether the characters match.

99.string.replace(regExpression,replaceString) replaces the existing string.

100.string.split (separator) returns an array to store the value.

101.string.substr(start[,length]) takes the string from the digit to the specified length.

102.string.toLowerCase() makes the string all lowercase.

103.string.toUpperCase() makes all characters uppercase.

104.parseInt(string[,radix(representing base)]) is forced to convert to integer type.

105.parseFloat(string[,radix]) is forced to convert to floating point type.

106.isNaN (variable): Test whether it is a numeric type.

107. Keywords for defining constants: const, keywords for defining variables: var

In the end, I still didn’t get the one hundred and eight generals. I’m just a little sorry. Is it okay if my friends can help make up?