input输入框加入限制只能输入正整数，输入其他字符会自动清除：
<inputtype="text"value="1"οnkeyup="if(this.value.length==1){this.value=this.value.replace(/[^1-9]/g,'')}else{this.value=this.value.replace(/\D/g,'')}"onafterpaste="if(this.value.length==1){this.value=this.value.replace(/[^1-9]/g,'0')}else{this.value=this.value.replace(/\D/g,'')}"/>
