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<html> <head> 问<meta charset="UTF-8"> <title></title> <style type="text/css"> a{ 50px; height: 50px; background: red; } </style> </head> <body> <script> var number; function clicke() { var a = document.getElementById("mya"); a.style.cssText +="; display:block; 100%;height:200px;background: yellow;"; } </script> <a id="mya" href="#" onclick="clicke()">点击我答</a> </body></html>$("#mya").addClass("on");