<h3>輸入完按回車後即可驗證!</h3>
正整數: <input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^\d+$/.test(this.value));">
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負整數: <input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-\d+$/.test(this.value));">
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整　數: <input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-?\d+$/.test(this.value));">
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正小數: <input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^\d+\.\d+$/.test(this.value));">
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負小數: <input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-\d+\.\d+$/.test(this.value));">
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小　數: <input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-?\d+\.\d+$/.test(this.value));">
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實　數: <input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-?\d+\.?\d*$/.test(this.value));">
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保留1位小數:<input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-?\d+\.?\d{0,1}$/.test(this.value));">
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保留2位小數:<input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-?\d+\.?\d{0,2}$/.test(this.value));">
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保留3位小數:<input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-?\d+\.?\d{0,3}$/.test(this.value));">

JS正則驗證兩位小數，驗證數字最簡單正則表達式大全