var character = carname[7]; 字符串的索引从 0 开始,这意味着第一个字符索引值为[0],第二个为[1],以此类推。 实例 constname="RUNOOB"; let letter=name[2]; document.getElementById("demo").innerHTML=letter; 尝试一下 » 你可以在字符串中使用引号,字符串中
JavaScript核心对象详解:Array提供数组操作方法如push、pop;String包含文本处理函数如substring、toUpperCase;Date对象管理日期时间,含getFullYear等方法;Math对象提供数学计算功能如random、sqrt;RegExp支持正则表达式匹配,含test、exec方...
for(let character of text) { let count = this.letterCounts.get(character); // Get old count this.letterCounts.set(character, count+1); // Increment it this.totalLetters++; } } // Convert the histogram to a string that displays an ASCII graphic toString() { // Convert the Map to a...
Get the third letter of name: constname ="W3Schools"; letletter = name.at(2); Try it Yourself » Get the third letter of name: constname ="W3Schools"; letletter = name[2]; Try it Yourself » Theat()method returns the character at a specified index (position) in a string. ...
“Control character in string: {a}.” : “在字符串中出现了Control的字符”, “Avoid \\’.” : “避免 \\”, “Avoid \\v.” : “避免 \\v”, “Avoid \\x-.” : “避免 \\x-”, “Bad escapement.” : “错误的转义字符”, ...
* @returns {string} - The middle character(s) of the string. */ function test(text) { // Get the length of the input string var text_len = text.length; // Check if the length of the string is odd or even if (text_len % 2 != 0) { // Calculate the start index for odd-...
String.fromCharCode(n1,n2, ...,nX) Parameters ParametersDescription n1,n2,nXRequired. One or more Unicode values to be converted. Return Value TypeDescription A stringA string representing the unicode character(s). Tip For a list of all Unicode values, please study ourComplete Unicode Reference...
var charCode = EventUtil.getCharCode(event); if (!/\d/.test(String.fromCharCode(charCode)) && charCode > 9 && !event.ctrlKey) { EventUtil.preventDefault(event); } }) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
varformId = document.getElementById("form"); console.log(formId); 2. 通过document.forms 取得页面中的所有表单元素,然后通过索引来取到对应的form元素,如下代码所示:取得页面第一个form元素; console.log(document.forms[0]); 3. 通过from表单中的name属性来获取,代码如下: ...
// first charactersubstr1 = string.substring(0,1); console.log(substr1);// P // if start > end, they are swappedsubstr2 = string.substring(1,0); console.log(substr2);// P// From 11th to last charactersubstr3 = string.substring(10);console.log(substr3);// JavaScript Tutorials//...