String String object
(1)String attributes
This object has only one attribute, length, which represents the length of the string. The number of characters, including all spaces and symbols:
var test_var = "I love You!"; document.write(test_var.length);
The displayed result is "11" because the string length also counts symbols and spaces:
Methods to access string objects:
Use the toUpperCase() method of the String object to convert the string lowercase letters to uppercase:
var mystr="Hello world!"; var mynum=mystr.toUpperCase();
The above code is executed Finally, the value of mynum is: HELLO WORLD!
(2)String method
String The object has a total of 19 built-in methods , mainly including functions such as the display of strings on the page, font size, font color, character search, and character case conversion. The following are some commonly used ones:
charAt(n) : Returns the nth single character of the string. (Counting from 0)
charCodeAt(n): Returns the ASCII code of a single character at the nth position of the string.
indexOf() : Usage: string_1.indexOf(string_2,n); Start searching from the nth position of string string_1, search for string_2, and return the found position, if not found , then -1 is returned, n can be left blank, and the search starts from the 0th position by default.
lastIndexOf(): Similar to indexOf(), but starting from the back.
split('separator') : Separate the string according to the specified delimiter and return an array, for example: '1&2&345&678'.split('&'); Return an array :1,2,345,678.
substring(n,m) : Returns the substring of the original string from position n to position m.
substr(n,x) : Returns the substring of the original string starting at position n and having a length of x.
toLowerCase(): Returns a string in which all uppercase letters of the original string are changed to lowercase.
toUpperCase() : Returns a string in which all lowercase letters of the original string are changed to uppercase.
Calculate the length of the string
<html> <body> <script type="text/javascript"> var txt="Hello World!" document.write(txt.length) </script> </body> </html>
Add styles to the string
<html>
<body>
<script type="text/javascript">
var txt="Hello World!"
document.write("<p>Big: " + txt.big() + "</p>")
document.write("<p>Small: " + txt.small() + "</p>")
document.write("<p>Bold: " + txt.bold() + "</p>")
document.write("<p>Italic: " + txt.italics() + "</p>")
document.write("<p>Blink: " + txt.blink() + " (does not work in IE)</p>")
document.write("<p>Fixed: " + txt.fixed() + "</p>")
document.write("<p>Strike: " + txt.strike() + "</p>")
document.write("<p>Fontcolor: " + txt.fontcolor("Red") + "</p>")
document.write("<p>Fontsize: " + txt.fontsize(16) + "</p>")
document.write("<p>Lowercase: " + txt.toLowerCase() + "</p>")
document.write("<p>Uppercase: " + txt.toUpperCase() + "</p>")
document.write("<p>Subscript: " + txt.sub() + "</p>")
document.write("<p>Superscript: " + txt.sup() + "</p>")
document.write("<p>Link: " + txt.link("//m.sbmmt.com") + "</p>")
</script>
</body>
</html>