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<html lang="en"><head> <meta charset="UTF-8"> <title>Copy Value</title></head><body><style></style><input type="text" name="" id="J_From"><input type="button" value="添加" id="J_Add"><input type="text" name="" id="J_To" readonly><script>(function(){ var f = document.getElementById(‘J_From‘), t = document.getElementById(‘J_To‘), b = document.getElementById(‘J_Add‘); b.onclick = function() { var val = f.value; val = ‘+‘ + val; t.value = val; };})();</script></body></html>原文：http://www.cnblogs.com/aixinxing-cn/p/5812038.html