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<title> 驗證數字最簡單正則表達式大全 </title>
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<h3>輸入完按回車後即可驗證！（自認為最簡單！）</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+)?$/.test(this.value));" />
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保留1位小數:<input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-?/d+(/./d{1,1})?$/.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{1,2})?$/.test(this.value));" />
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保留3位小數:<input type="text" size="20" onkeydown="if(event.keyCode == 13) alert(/^-?/d+(/./d{1,3})?$/.test(this.value));" />
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