對於JS初學者來講,一個完整的購物車實現仍是挺難的,邏輯功能挺多。寫出完整功能,能提高很多JS基礎,下面實現購物車全選多選按鈕功能:html
首先HTML及CSS部分:this
<style> table { border-collapse: collapse; } td { border: 1px solid #000000; width: 100px; height: 30px; text-align: center; } </style> <body> <table> <tr> <td> <label for="allCheck">全選</label><br><input id="allCheck" type="checkbox"> </td> </tr> <tr> <td> <input id="check0" type="checkbox"> </td> </tr> <tr> <td> <input id="check1" type="checkbox"> </td> </tr> <tr> <td> <input id="check2" type="checkbox"> </td> </tr> <tr> <td> <input id="check3" type="checkbox"> </td> </tr> <tr> <td> <input id="check4" type="checkbox"> </td> </tr> </table>
而後是JS部分:spa
<script> var allcheck = document.getElementById("allCheck") //獲取全選框 allcheck.addEventListener("click",clickHandler) //給全選框按鈕添加點擊屬性 for(var i=0;i<5;i++){ var check = document.getElementById("check"+i) //遍歷每一個多選按鈕 check.addEventListener("click",clickHandler); //給每一個多選框添加點擊屬性 } function clickHandler(){ if(allcheck === this){ //進行判斷 若是你點擊的是全選按鈕 那麼多選按鈕也就所有被選中 for(var i=0;i<5;i++){ var check = document.getElementById("check"+i); check.checked = allcheck.checked; } return; //結束 } for(var j=0;j<5;j++){ var checks = document.getElementById("check"+j); if(!checks.checked){ 這一部分代碼用來多選按鈕是否被選中 遍歷全部的多選按鈕 若是有一個多選按鈕沒有被選中 那麼全選按鈕就不會被選中 allcheck.checked = false; return; //結束 } } allcheck.checked = true; //很差理解 看不懂能夠一步一步運行代碼 } </script>
所有代碼:code
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> table { border-collapse: collapse; } td { border: 1px solid #000000; width: 100px; height: 30px; text-align: center; } </style> </head> <body> <table> <tr> <td> <label for="allCheck">全選</label><br><input id="allCheck" type="checkbox"> </td> </tr> <tr> <td> <input id="check0" type="checkbox"> </td> </tr> <tr> <td> <input id="check1" type="checkbox"> </td> </tr> <tr> <td> <input id="check2" type="checkbox"> </td> </tr> <tr> <td> <input id="check3" type="checkbox"> </td> </tr> <tr> <td> <input id="check4" type="checkbox"> </td> </tr> </table> <script> var allcheck = document.getElementById("allCheck") allcheck.addEventListener("click",clickHandler) for(var i=0;i<5;i++){ var check = document.getElementById("check"+i) check.addEventListener("click",clickHandler); } function clickHandler(){ if(allcheck === this){ for(var i=0;i<5;i++){ var check = document.getElementById("check"+i); check.checked = allcheck.checked; } return; } for(var j=0;j<5;j++){ var checks = document.getElementById("check"+j); if(!checks.checked){ allcheck.checked = false; return; } } allcheck.checked = true; } </script> </body> </html>
效果以下:htm