javascript当中eval用法
1）eval 例 4.1.1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"/> </head> <BODY> <SCRIPT LANGUAGE="JavaScript"> <!-- /*马克-to-win：var scriptCode = "c = a * b"; var a = 5; var b = 10; var c = 2; eval(scriptCode); 以上的话就相当于： eval("c = a * b");===c = a * b eval是global的方法， */ var result = window.eval("1+2/4") ;//根据上面所说，result=1+2/4； document.write(result) var s="today=new Date();document.write(today.toLocaleString())" eval(s) //--> </SCRIPT> </BODY> </HTML> 例 4.1.2 <HTML> <HEAD> <meta http-equiv="content-type" content="text/html; charset=utf-8"/> <TITLE>在eclipse中直接open with火狐即可</TITLE> </HEAD> <BODY> <SCRIPT LANGUAGE="JavaScript"> <!-- //例1 var s = "2+31-18"; /*When the eval() function is called, it expects a string to be passed to it as its single argument value. The contents of that string should be syntactically correct executable script source text.*/ document.write(eval(s)); var s1 = "2+31a-18"; /* note that we must comment out the following statement, otherwise, it reports error.*/ //document.write(eval(s1)); //例2 eval("d =new Date();document.write(d.toLocaleString())") //eval()函数的参数为字符串，功能是将该字符串执行出来。体会“执行”的意思！ //--> </SCRIPT> </BODY> </HTML>
更多请见： https://blog.csdn.net/qq_43650923/article/details/102216676
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