JavaScript 数据类型转换

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显式类型转换(强制类型转换)
parseInt()、 parseFloat()

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>无标题文档</title><script>window.onload=function (){    var oTxt1=document.getElementById('txt1');    var oTxt2=document.getElementById('txt2');    var oBtn=document.getElementById('btn1');    oBtn.onclick=function ()    {        alert(parseInt(oTxt1.value)+parseInt(oTxt2.value));    };};</script></head><body><input id="txt1" type="text" /><input id="txt2" type="text" /><input id="btn1" type="button" value="求和" /></body></html>

隐式类型转换
==、===
减法

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>无标题文档</title><script>var a='12';var b=12;alert(a==b);    //先把两边的东西转成一样的类型，然后再比较//alert(a===b); //不转换，直接比较</script></head><body></body></html>

参考：JavaScript

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