getElementById() 根据id获取dom元素
没有找到则返会Null
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> </head> <body> <div id="box"></div> <script> var box=document.getElementById("box"); console.log(box);//<div id="box"></div> var boxs=document.getElementById("boxs"); console.log(boxs);//null </script> </body> </html>
在不同的范围内查找dom元素
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> </head> <body> <ul id="list"> <li>li</li> <li>li</li> <li>li</li> <li>li</li> <li>li</li> </ul> <ol> <li>li</li> <li>li</li> </ol> <script> var ul=document.getElementById("list"); var lis1=ul.getElementsByTagName("li"); console.log(lis1.length);//5 var lis2=document.getElementsByTagName("li"); console.log(lis2.length);//7 </script> </body> </html>
设置元素的css样式
ele.style.属性=属性值
如果是连字符形式的，需要转换为驼峰形式
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> </head> <body> <ul id="list"> <li>li</li> <li>li</li> <li>li</li> <li>li</li> <li>li</li> </ul> <ol id="list2"> <li>li</li> <li>li</li> </ol> <script> var ul=document.getElementById("list"); ul.style.color="red"; var ol=document.getElementById("list2"); ol.style.fontWeight="bold"; </script> </body> </html>
设置数组元素的样式
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> </head> <body> <ul id="list"> <li>li</li> <li>li</li> <li>li</li> <li>li</li> <li>li</li> </ul> <ol id="list2"> <li>li</li> <li>li</li> </ol> <script> var ul=document.getElementById("list"); ul.style.color="red"; var ol=document.getElementById("list2"); var lis=ol.getElementsByTagName("li"); lis[0].style.backgroundColor="pink"; lis[1].style.backgroundColor="#abcdef"; </script> </body> </html>
innerHTML 获取和设置元素的内容，包括html标签和文本
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> </head> <body> <ol id="list2"> <li>咪咪</li> <li>灰灰</li> </ol> <script> var ol=document.getElementById("list2"); var lis=ol.getElementsByTagName("li"); for(var i=0,len=lis.length;i<len;i++){ lis[i].innerHTML+='~~~'; console.log(lis[i].innerHTML); } </script> </body> </html>
className 设置和获取元素的类
设置的类会把原来的类替换掉
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <style> .orange{color:orange;} </style> </head> <body> <ol id="list2"> <li>咪咪</li> <li>灰灰</li> </ol> <script> var ol=document.getElementById("list2"); var lis=ol.getElementsByTagName("li"); lis[0].className="orange"; console.log(lis[0].className); </script> </body> </html>
getAttribute() 获取属性
自定义属性建议都以 data- 开头
ele.属性名 直接获取属性（标签自带属性，除了class为className)
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <style> .orange{color:orange;} </style> </head> <body> <p id="p" class="pp" data-type="title"></p> <input id="text" type="text" name="text" value="hh" validate="true"> <script> var p=document.getElementById("p"); console.log(p.id);//p console.log(p.className);//pp console.log(p.getAttribute("data-type"));//title var text=document.getElementById("text"); console.log(text.type);//text console.log(text.name);//text console.log(text.value);//hh console.log(text.getAttribute("validate"));//true </script> </body> </html>
setAttribute() removeAttribute() 给dom元素设置和删除属性
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <style> .orange{color:orange;} </style> </head> <body> <p id="p" class="pp" data-type="title"></p> <script> var p=document.getElementById("p"); p.setAttribute("data-color","orange"); console.log(p.getAttribute("data-color"));//orange p.removeAttribute("data-color"); console.log(p.getAttribute("data-color"));//null </script> </body> </html>