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What are the commonly used attribute methods in JavaScript?

coldplay.xixi

Apr 08, 2021 pm 02:02 PM

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Commonly used attribute methods in JavaScript include: 1. The comment in JS is [//]; 2. Convert character type to numeric type [parseInt()]; 3. Get the length of the string [length]; 4. Use var to declare variables; 5. Judgment statement structure [if(condition){}else{}].

What are the commonly used attribute methods in JavaScript?

The operating environment of this tutorial: Windows 7 system, JavaScript version 1.8.5, DELL G3 computer.

Commonly used attribute methods in JavaScript are:

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

2. The comment in JS is/ /

3. The traditional HTML document sequence 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 lowercase to uppercase JS:

document.getElementById("output").value=document.getElementById("input").value.toUpperCase();

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

8. Convert character types into numerical types in JS: parseInt(), parseFloat()

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

10. Get the string length in JS: (length)

11.JS Characters are connected with characters using numbers.

12. The comparison operators in JS are: ==Equal,!=Not equal,>;,>;=,<.<=

13. Use var to declare variables in JS.

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

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

16. The command to terminate the loop is: break

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

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

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

20. Status bar Setting: 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 output stream of the document: document.close();

27. String append connector: =

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

29. Get the element method: document.getElementById()

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

var form = window.document.forms[0]
for (var i = 0; i<form.elements.length;i ){
if (form.elements.type == "text"){
form.elements.value = "";
}
}

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31. Determine whether the check button is checked in JS:

     document.forms[0].checkThis.checked

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(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):

Get the length of the radio button group document.forms[0].groupName.length

33. Checked is also used to determine whether the radio button group is selected.

34. The value of the drop-down list box:

     document.forms[0].selectName.options[n].value

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(nSometimes the name of the drop-down list box plus .selectedIndex is used to determine Determine the selected value)

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

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

37. Return the position where string 2 appears in string 1: String1.indexOf("String2")!=-1 means there is no Find.

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

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

40. Math functions:

Math.PI (returns pi), Math.SQRT2 (returns square root), Math.max(value1, value2) returns The

of the two numbers is the most valuable, 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 variable: var today = new Date();

42. Date function list:

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 the day, dateObj.getDay() gets the date,
dateObj.getHours() gets the hours, dateObj.getMinutes() gets the minutes, dateObj.getSeconds() gets seconds,
dateObj.setTime(value)设置时间,dateObj.setYear(val)设置年,
dateObj.setMonth(val)设置月,dateObj.setDate(val)设置日,
dateObj.setDay(val)设置星期几,dateObj.setHours设置小时,dateObj.setMinutes(val)设置分,
dateObj.setSeconds(val)设置秒 [注意:此日期时间从0开始计]

43.FRAME的表示方式:

     [window.]frames[n].ObjFuncVarName,frames["frameName"].ObjFuncVarName,frameName.ObjFuncVarName

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44.parent代表父亲对象,top代表最顶端对象

45.打开子窗口的父窗口为:opener

46.表示当前所属的位置:this

47.当在超链接中调用JS函数时用:(javascript :)来开头后面加函数名

48.在老的浏览器中不执行此JS:;

49.引用一个文件式的JS:;

50.指定在不支持脚本的浏览器显示的HTML: